Tgf beta receptor antagonists

ABSTRACT

The invention relates generally to compounds of formula (I) that modulate the activity of TGFβR-1 and TGFβR-2, pharmaceutical compositions containing said compounds and methods of treating proliferative disorders and N disorders of dysregulated apoptosis, such as cancer, utilizing the compounds of the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/442,580, filed Jan. 5, 2017, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to compounds that modulate the activity of TGFβR-1 and TGFβR-2, pharmaceutical compositions containing said compounds and methods of treating proliferative disorders and disorders of dysregulated apoptosis, such as cancer, utilizing the compounds of the invention.

BACKGROUND OF THE INVENTION

TGFβ is a multifunctional cytokine that regulates a wide variety of biological processes that include cell proliferation and differentiation, migration and adhesion, extracellular matrix modification including tumor stroma and immunosuppression, angiogenesis and desmoplasia (Ling and Lee, Current Pharmaceutical Biotech. 2011, 12:2190-2202), processes supporting tumor progression and late stage disease.

The active form of TGFβ is a dimer that signals through the formation of a membrane bound heterotetramer composed of the serine threonine type 1 and type 2 receptors, TGFβR-1 (ALK5) and TGFβR-2, respectively. Upon binding of two type 1 and two type 2 receptors, the type 2 constitutively activated receptors phosphorylate the type 1 receptors in the glycine and serine rich “GS region” activating a signaling cascade through the intracellular signaling effector molecules, Smad2 or Smad3. TGFβR-1 phosphorylates the receptor Smad2 and/or Smad3 (RSmads) that form a complex with Smad4 (Shi and Massague, Cell 2003, 113:685-700). These complexes then translocate to the nucleus where they elicit a wide variety of transcriptional responses resulting in altered gene expression (Weiss and Attisano, WIREs Developmental Biology, 2013, 2:47-63). The TGFβ proteins are prototypic members of a large family of related factors in mammals with a number of these also identified in other phyla. Generally, two groups have been characterized, the TGFβ-like and BMP-like ligands. In addition, in vertebrates, seven type1 receptors and five type 2 receptors have been identified. An additional layer of complexity in ligand/receptor binding is the potential of co-receptors known as type 3 that facilitate ligand binding to the type 1 and 2 receptor complex. These type 3 receptors, also known as Betaglycan and Endoglin are comprised of large extracellular domains and short cytoplasmic tails and bind different TGFβ family members (Bernabeu et al., Biochem Biophys Acta 2009, 1792:954-73). Although type 3 receptors facilitate signaling, cleavage of the extracellular domain can generate soluble proteins that sequester ligands and can potentially inhibit signaling (Bemabeu et al., Biochem Biophys Acta 2009, 1792:954-73). While multiple redundancies in this large family present challenges to identifying a selective inhibitor, TGFβR-1 and -2 are relatively selective targets for TGFβ ligand engagement.

Alteration in TGFβ signaling are associated with a wide variety of human disorders including fibrosis, inflammatory, skeletal, muscular and cardiovascular disorders as well as cancer (Harradine, et al, 2006, Annals of Medicine 38:403-14). In human cancer, TGFβ signaling alterations can occur in the germline or arise spontaneously in various cancer types. TGFβ is also a potent inducer of angiogenesis, which provides a critical support system for solid tumors as well as a mechanism for tumor cell dissemination (Buijs et al., 2011, Curr Pharmaceutical Biotech, 12:2121-37). Therefore multiple strategies to inhibit TGFβ signaling have been exploited in various disease states.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, there is provided a compound having the structure of formula (I):

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof,

wherein

A is a 5-8 membered heterocyclic ring or a 10-12 membered heterobicyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

-   -   each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or         C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In another aspect, there is provided a pharmaceutical composition comprising a compound of the invention or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, diluents or excipients.

In another aspect, there is provided a compound of the invention or a pharmaceutically acceptable salt thereof for use in therapy. In particular, for use in the treatment of a disease or condition for which a TGFßR antagonist is indicated.

In another aspect, there is provided a method of treating cancers, fibrosis, inflammatory, skeletal, muscular and cardiovascular disorders which comprise administering to a subject in need thereof a therapeutically effective amount of a TGFßR antagonist.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect of the present invention, there is provided a compound having the structure of formula (I):

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof,

wherein

A is a 5-8 membered heterocyclic ring or a 10-12 membered heterobicyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In a second aspect within the scope of the first aspect of the invention, there is provided a compound of formula (I)

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof,

wherein

A is pyridyl substituted with 0-3 R⁴ groups;

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In a third aspect within the scope of the first and second aspects of the invention, there is provided a compound of formula (I) wherein

A is pyridyl substituted with 0-2 R⁴ groups;

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In a fourth aspect within the scope of the first, second and third aspects of the invention, there is provided a compound of formula (I) wherein

Z is

and n is 0, 1 or 2.

In a fifth aspect of the invention, there is provided a compound of formula (I) wherein

Z is

and n is 0, 1 or 2.

In a sixth aspect of the invention, there is provided a compound of formula (I) wherein

Z is

and n is 0, 1 or 2.

In a seventh aspect of the invention, there is provided a compound of formula (I) wherein

Z is

and n is 0, 1 or 2.

In another aspect of the invention within the scope of the prior seven aspects, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.

In another aspect of the invention within the scope of the prior seven aspects, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.

In another aspect of the invention within the scope of the prior seven aspects, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.

In another aspect of the invention within the scope of the prior seven aspects, there is provided a compound of the following structure

In another aspect of the invention within the scope of the prior seven aspects, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.

In another aspect of the invention, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof,

wherein

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In another aspect of the invention, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof,

wherein

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In another aspect of the invention, there is provided a compound of the following structure

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof,

wherein

each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN;

Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl;

R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—;

each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and

R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.

In another aspect, there is provided a compound selected from the exemplified examples within the scope of the first aspect, or a pharmaceutically acceptable salt, tautomer or stereoisomer thereof.

In another aspect, there is provided a compound selected from any subset list of compounds within the scope of any of the above aspects.

Other Embodiments of the Invention

In another embodiment, the invention provides a pharmaceutical composition, comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of at least one of the compounds of the invention or a stereoisomer, a tautomer, a pharmaceutically acceptable salt, or a solvate thereof.

In another embodiment, the invention provides a process for making a compound of the invention or a stereoisomer, a tautomer, a pharmaceutically acceptable salt, or a solvate thereof.

In another embodiment, the invention provides a method for the treatment and/or prophylaxis of various types of cancer, comprising administering to a patient in need of such treatment and/or prophylaxis a therapeutically effective amount of one or more compounds of the invention, alone, or, optionally, in combination with another compound of the invention and/or at least one other type of therapeutic agent.

In another embodiment, the invention provides a method for the treatment and/or prophylaxis of various types of cancer, including without limitation, small cell lung cancer, non-small cell lung cancer, colorectal cancer, multiple myeloma, acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), pancreatic cancer, liver cancer, hepatocellular cancer, neuroblastoma, other solid tumors or other hematological cancers.

In another embodiment, the invention provides a method for the treatment and/or prophylaxis of various types of cancer, including without limitation, small cell lung cancer, non-small cell lung cancer, triple-negative breast cancer, colorectal cancer, prostate cancer, melanoma, pancreatic cancer, multiple myeloma, T-acute lymphoblastic leukemia or AML.

In another embodiment, the invention provides a method for the treatment and/or prophylaxis of Marfan's syndrome and associated diseases, disorders and conditions associated with aberrant TGF-β expression.

In another embodiment, the invention provides a method for the treatment and/or prophylaxis of fibrosis such as hepatic or pulmonary fibrosis.

In another embodiment, the invention provides a compound of the present invention for use in therapy.

In another embodiment, the invention provides a combined preparation of a compound of the present invention and additional therapeutic agent(s) for simultaneous, separate or sequential use in therapy.

Therapeutic Applications

The compounds of formula (I) of the invention are TGFßR antagonists and have potential utility in the treatment of diseases and conditions for which a TGFßR antagonist is indicated.

In one embodiment there is provided a method for the treatment of a disease or condition, for which a TGFßR antagonists is indicated, in a subject in need thereof which comprises administering a therapeutically effective amount of compound of formula (I) or a pharmaceutically acceptable salt thereof.

In another embodiment there is provided a method for treatment of a chronic autoimmune and/or inflammatory condition, in a subject in need thereof which comprises administering a therapeutically effective amount of one or more compounds of formula (I) or a pharmaceutically acceptable salt thereof.

In a further embodiment there is provided a method for treatment of cancer in a subject in need thereof which comprises administering a therapeutically effective amount of one or more compounds of formula (I) or a pharmaceutically acceptable salt thereof.

In one embodiment the subject in need thereof is a mammal, particularly a human.

TGFßR antagonists are believed to be useful in the treatment of a variety of diseases or conditions related to systemic or tissue inflammation, inflammatory responses to infection or hypoxia, cellular activation and proliferation, lipid metabolism, fibrosis and in the prevention and treatment of viral infections.

TGFßR antagonists may be useful in the treatment of fibrotic conditions such as idiopathic pulmonary fibrosis, renal fibrosis, post-operative stricture, keloid formation, scleroderma and cardiac fibrosis.

TGFßR antagonists may be useful in the treatment of cancer, including hematological, epithelial including lung, breast and colon carcinomas, midline carcinomas, mesenchymal, hepatic, renal and neurological tumours.

The term “diseases or conditions for which a TGFßR antagonists is indicated” is intended to include any of or all of the above disease states.

While it is possible that for use in therapy, a compound of formula (I) as well as pharmaceutically acceptable salts thereof may be administered as the compound itself, it is more commonly presented as a pharmaceutical composition.

Pharmaceutical compositions may be presented in unit dose forms containing a predetermined amount of active ingredient pep unit dose. Preferred unit dosage compositions are those containing a daily dose or sub-dose, or an appropriate fraction thereof, of an active ingredient. Such unit doses may therefore be administered more than once a day. Preferred unit dosage compositions are those containing a daily dose or sub-dose (for administration more than once a day), as herein above recited, or an appropriate fraction thereof, of an active ingredient.

Types of cancers that may be treated with the compounds of this invention include, but are not limited to, brain cancers, skin cancers, bladder cancers, ovarian cancers, breast cancers, gastric cancers, pancreatic cancers, prostate cancers, colon cancers, blood cancers, lung cancers and bone cancers. Examples of such cancer types include neuroblastoma, intestine carcinoma such as rectum carcinoma, colon carcinoma, familiar adenomatous polyposis carcinoma and hereditary non-polyposis colorectal cancer, esophageal carcinoma, labial carcinoma, larynx carcinoma, hypopharynx carcinoma, tong carcinoma, salivary gland carcinoma, gastric carcinoma, adenocarcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, renal carcinoma, kidney parenchymal carcinoma, ovarian carcinoma, cervix carcinoma, uterine corpus carcinoma, endometrium carcinoma, chorion carcinoma, pancreatic carcinoma, prostate carcinoma, testis carcinoma, breast carcinoma, urinary carcinoma, melanoma, brain tumors such as glioblastoma, astrocytoma, meningioma, medulloblastoma and peripheral neuroectodermal tumors, Hodgkin lymphoma, non-Hodgkin lymphoma, Burkitt lymphoma, acute lymphatic leukemia (ALL), chronic lymphatic leukemia (CLL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), adult T-cell leukemia lymphoma, diffuse large B-cell lymphoma (DLBCL), hepatocellular carcinoma, gall bladder carcinoma, bronchial carcinoma, small cell lung carcinoma, non-small cell lung carcinoma, multiple myeloma, basalioma, teratoma, retinoblastoma, choroid melanoma, seminoma, rhabdomyosarcoma, craniopharyngioma, osteosarcoma, chondrosarcoma, myosarcoma, liposarcoma, fibrosarcoma, Ewing sarcoma and plasmocytoma.

In addition to apoptosis defects found in tumors, defects in the ability to eliminate self-reactive cells of the immune system due to apoptosis resistance are considered to play a key role in the pathogenesis of autoimmune diseases. Autoimmune diseases are characterized in that the cells of the immune system produce antibodies against its own organs and molecules or directly attack tissues resulting in the destruction of the latter. A failure of those self-reactive cells to undergo apoptosis leads to the manifestation of the disease. Defects in apoptosis regulation have been identified in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis.

Compounds of the invention are useful for the treatment of certain types of cancer by themselves or in combination or co-administration with other therapeutic agents or radiation therapy. Thus, in one embodiment, the compounds of the invention are co-administered with radiation therapy or a second therapeutic agent with cytostatic or antineoplastic activity. Suitable cytostatic chemotherapy compounds include, but are not limited to (i) antimetabolites; (ii) DNA-fragmenting agents, (iii) DNA-crosslinking agents, (iv) intercalating agents (v) protein synthesis inhibitors, (vi) topoisomerase I poisons, such as camptothecin or topotecan; (vii) topoisomerase II poisons, (viii) microtubule-directed agents, (ix) kinase inhibitors (x) miscellaneous investigational agents (xi) hormones and (xii) hormone antagonists. It is contemplated that compounds of the invention may be useful in combination with any known agents falling into the above 12 classes as well as any future agents that are currently in development. In particular, it is contemplated that compounds of the invention may be useful in combination with current Standards of Care as well as any that evolve over the foreseeable future. Specific dosages and dosing regimens would be based on physicians' evolving knowledge and the general skill in the art.

Further provided herein are methods of treatment wherein compounds of the invention are administered with one or more immuno-oncology agents. The immuno-oncology agents used herein, also known as cancer immunotherapies, are effective to enhance, stimulate, and/or up-regulate immune responses in a subject. In one aspect, the administration of a compound of the invention with an immuno-oncology agent has a synergic effect in inhibiting tumor growth.

In one aspect, the compound(s) of the invention are sequentially administered prior to administration of the immuno-oncology agent. In another aspect, compound(s) of the invention are administered concurrently with the immunology-oncology agent. In yet another aspect, compound(s) of the invention are sequentially administered after administration of the immuno-oncology agent.

In another aspect, compounds of the invention may be co-formulated with an immuno-oncology agent.

Immuno-oncology agents include, for example, a small molecule drug, antibody, or other biologic or small molecule. Examples of biologic immuno-oncology agents include, but are not limited to, cancer vaccines, antibodies, and cytokines. In one aspect, the antibody is a monoclonal antibody. In another aspect, the monoclonal antibody is humanized or human.

In one aspect, the immuno-oncology agent is (i) an agonist of a stimulatory (including a co-stimulatory) receptor or (ii) an antagonist of an inhibitory (including a co-inhibitory) signal on T cells, both of which result in amplifying antigen-specific T cell responses (often referred to as immune checkpoint regulators).

Certain of the stimulatory and inhibitory molecules are members of the immunoglobulin super family (IgSF). One important family of membrane-bound ligands that bind to co-stimulatory or co-inhibitory receptors is the B7 family, which includes B7-1, B7-2, B7-H1 (PD-L1), B7-DC (PD-L2), B7-H2 (ICOS-L), B7-H3, B7-H4, B7-H5 (VISTA), and B7-H6. Another family of membrane bound ligands that bind to co-stimulatory or co-inhibitory receptors is the TNF family of molecules that bind to cognate TNF receptor family members, which includes CD40 and CD40L, OX-40, OX-40L, CD70, CD27L, CD30, CD30L, 4-1BBL, CD137 (4-1BB), TRAIL/Apo2-L, TRAILR1/DR4, TRAILR2/DR5, TRAILR3, TRAILR4, OPG, RANK, RANKL, TWEAKR/Fn14, TWEAK, BAFFR, EDAR, XEDAR, TACI, APRIL, BCMA, LTβR, LIGHT, DcR3, HVEM, VEGI/TL1A, TRAMP/DR3, EDAR, EDA1, XEDAR, EDA2, TNFR1, Lymphotoxin α/TNFβ, TNFR2, TNFα, LTβR, Lymphotoxin α1β2, FAS, FASL, RELT, DR6, TROY, NGFR.

In another aspect, the immuno-oncology agent is a cytokine that inhibits T cell activation (e.g., IL-6, IL-10, TGF-ß, VEGF, and other immunosuppressive cytokines) or a cytokine that stimulates T cell activation, for stimulating an immune response.

In one aspect, T cell responses can be stimulated by a combination of a compound of the invention and one or more of (i) an antagonist of a protein that inhibits T cell activation (e.g., immune checkpoint inhibitors) such as CTLA-4, PD-1, PD-L1, PD-L2, LAG-3, TIM-3, Galectin 9, CEACAM-1, BTLA, CD69, Galectin-1, TIGIT, CD113, GPR56, VISTA, 2B4, CD48, GARP, PD1H, LAIR1, TIM-1, and TIM-4, and (ii) an agonist of a protein that stimulates T cell activation such as B7-1, B7-2, CD28, 4-1BB (CD137), 4-1BBL, ICOS, ICOS-L, OX40, OX40L, GITR, GITRL, CD70, CD27, CD40, DR3 and CD28H.

Other agents that can be combined with compounds of the invention for the treatment of cancer include antagonists of inhibitory receptors on NK cells or agonists of activating receptors on NK cells. For example, compounds of the invention can be combined with antagonists of KIR, such as lirilumab.

Yet other agents for combination therapies include agents that inhibit or deplete macrophages or monocytes, including but not limited to CSF-1R antagonists such as

CSF-1R antagonist antibodies including RG7155 (WO11/70024, WO11/107553, WO11/131407, WO13/87699, WO13/119716, WO13/132044) or FPA-008 (WO11/140249; WO13169264; WO14/036357).

In another aspect, compounds of the invention can be used with one or more of agonistic agents that ligate positive costimulatory receptors, blocking agents that attenuate signaling through inhibitory receptors, antagonists, and one or more agents that increase systemically the frequency of anti-tumor T cells, agents that overcome distinct immune suppressive pathways within the tumor microenvironment (e.g., block inhibitory receptor engagement (e.g., PD-L1/PD-1 interactions), deplete or inhibit Tregs (e.g., using an anti-CD25 monoclonal antibody (e.g., daclizumab) or by ex vivo anti-CD25 bead depletion), inhibit metabolic enzymes such as IDO, or reverse/prevent T cell anergy or exhaustion) and agents that trigger innate immune activation and/or inflammation at tumor sites.

In one aspect, the immuno-oncology agent is a CTLA-4 antagonist, such as an antagonistic CTLA-4 antibody. Suitable CTLA-4 antibodies include, for example, YERVOY (ipilimumab) or tremelimumab.

In another aspect, the immuno-oncology agent is a PD-1 antagonist, such as an antagonistic PD-1 antibody. Suitable PD-1 antibodies include, for example, OPDIVO (nivolumab), KEYTRUDA (pembrolizumab), or MEDI-0680 (AMP-514; WO2012/145493). The immuno-oncology agent may also include pidilizumab (CT-011), though its specificity for PD-1 binding has been questioned. Another approach to target the PD-1 receptor is the recombinant protein composed of the extracellular domain of PD-L2 (B7-DC) fused to the Fc portion of IgG1, called AMP-224

In another aspect, the immuno-oncology agent is a PD-L1 antagonist, such as an antagonistic PD-L1 antibody. Suitable PD-L1 antibodies include, for example, MPDL3280A (RG7446; WO2010/077634), durvalumab (MED14736), BMS-936559 (WO2007/005874), and MSB0010718C (WO2013/79174).

In another aspect, the immuno-oncology agent is a LAG-3 antagonist, such as an antagonistic LAG-3 antibody. Suitable LAG3 antibodies include, for example, BMS-986016 (WO10/19570, WO14/08218), or IMP-731 or IMP-321 (WO008/132601, WO09/44273).

In another aspect, the immuno-oncology agent is a CD137 (4-1BB) agonist, such as an agonistic CD137 antibody. Suitable CD137 antibodies include, for example, urelumab and PF-05082566 (WO12/32433).

In another aspect, the immuno-oncology agent is a GITR agonist, such as an agonistic GITR antibody. Suitable GITR antibodies include, for example, BMS-986153, BMS-986156, TRX-518 (WO006/105021, WO009/009116) and MK-4166 (WO11/028683).

In another aspect, the immuno-oncology agent is an IDO antagonist. Suitable IDO antagonists include, for example, INCB-024360 (WO2006/122150, WO07/75598, WO008/36653, WO08/36642), indoximod, or NLG-919 (WO09/73620, WO009/1156652, WO11/56652, WO12/142237).

In another aspect, the immuno-oncology agent is an OX40 agonist, such as an agonistic OX40 antibody. Suitable OX40 antibodies include, for example, MEDI-6383 or MEDI-6469.

In another aspect, the immuno-oncology agent is an OX40L antagonist, such as an antagonistic OX40 antibody. Suitable OX40L antagonists include, for example, RG-7888 (WO06/029879).

In another aspect, the immuno-oncology agent is a CD40 agonist, such as an agonistic CD40 antibody. In yet another embodiment, the immuno-oncology agent is a CD40 antagonist, such as an antagonistic CD40 antibody. Suitable CD40 antibodies include, for example, lucatumumab or dacetuzumab.

In another aspect, the immuno-oncology agent is a CD27 agonist, such as an agonistic CD27 antibody. Suitable CD27 antibodies include, for example, varlilumab.

In another aspect, the immuno-oncology agent is MGA271 (to B7H3) (WO11/109400).

The combination therapy is intended to embrace administration of these therapeutic agents in a sequential manner, that is, wherein each therapeutic agent is administered at a different time, as well as administration of these therapeutic agents, or at least two of the therapeutic agents, in a substantially simultaneous manner. Substantially simultaneous administration can be accomplished, for example, by administering to the subject a single dosage form having a fixed ratio of each therapeutic agent or in multiple, single dosage forms for each of the therapeutic agents. Sequential or substantially simultaneous administration of each therapeutic agent can be effected by any appropriate route including, but not limited to, oral routes, intravenous routes, intramuscular routes, and direct absorption through mucous membrane tissues. The therapeutic agents can be administered by the same route or by different routes. For example, a first therapeutic agent of the combination selected may be administered by intravenous injection while the other therapeutic agents of the combination may be administered orally. Alternatively, for example, all therapeutic agents may be administered orally or all therapeutic agents may be administered by intravenous injection. Combination therapy also can embrace the administration of the therapeutic agents as described above in further combination with other biologically active ingredients and non-drug therapies (e.g., surgery or radiation treatment.) Where the combination therapy further comprises a non-drug treatment, the non-drug treatment may be conducted at any suitable time so long as a beneficial effect from the co-action of the combination of the therapeutic agents and non-drug treatment is achieved. For example, in appropriate cases, the beneficial effect is still achieved when the non-drug treatment is temporally removed from the administration of the therapeutic agents, perhaps by days or even weeks.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. This invention encompasses all combinations of preferred aspects of the invention noted herein. It is understood that any and all embodiments of the present invention may be taken in conjunction with any other embodiment or embodiments to describe additional embodiments. It is also understood that each individual element of the embodiments is its own independent embodiment. Furthermore, any element of an embodiment is meant to be combined with any and all other elements from any embodiment to describe an additional embodiment.

Pharmaceutical Compositions and Dosing

The invention also provides pharmaceutically acceptable compositions which comprise a therapeutically effective amount of one or more of the compounds of Formula I, formulated together with one or more pharmaceutically acceptable carriers (additives) and/or diluents, and optionally, one or more additional therapeutic agents described above. As described in detail below, the pharmaceutical compositions of the present invention may be specially formulated for administration in solid or liquid form, including those adapted for the following: (1) oral administration, for example, drenches (aqueous or non-aqueous solutions or suspensions), tablets, e.g., those targeted for buccal, sublingual, and systemic absorption, boluses, powders, granules, pastes for application to the tongue; (2) parenteral administration, for example, by subcutaneous, intramuscular, intravenous or epidural injection as, for example, a sterile solution or suspension, or sustained release formulation; (3) topical application, for example, as a cream, ointment, or a controlled release patch or spray applied to the skin; (4) intravaginally or intrarectally, for example, as a pessary, cream or foam; (5) sublingually; (6) ocularly; (7) transdermally; or (8) nasally.

The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

The phrase “pharmaceutically acceptable carrier” as used herein means a pharmaceutically acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, manufacturing aid (e.g., lubricant, talc magnesium, calcium or zinc stearate, or steric acid), or solvent encapsulating material, involved in carrying or transporting the subject compound from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as pharmaceutically-acceptable carriers include: (1) sugars, such as lactose, glucose and sucrose; (2) starches, such as corn starch and potato starch; (3) cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients, such as cocoa butter and suppository waxes; (9) oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; (10) glycols, such as propylene glycol; (11) polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffering agents, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethyl alcohol; (20) pH buffered solutions; (21) polyesters, polycarbonates and/or polyanhydrides; and (22) other non-toxic compatible substances employed in pharmaceutical formulations.

Wetting agents, emulsifiers and lubricants, such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, release agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the compositions.

Examples of pharmaceutically-acceptable antioxidants include: (1) water soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; (2) oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propyl gallate, alpha-tocopherol, and the like; and (3) metal chelating agents, such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol, tartaric acid, phosphoric acid, and the like.

Formulations of the present invention include those suitable for oral, nasal, topical (including buccal and sublingual), rectal, vaginal and/or parenteral administration. The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. The amount of active ingredient which can be combined with a carrier material to produce a single dosage form will vary depending upon the patient being treated and the particular mode of administration. The amount of active ingredient which can be combined with a carrier material to produce a single dosage form will generally be that amount of the compound which produces a therapeutic effect. Generally, out of one hundred percent, this amount will range from about 0.1 percent to about ninety-nine percent of active ingredient, preferably from about 5 percent to about 70 percent, most preferably from about 10 percent to about 30 percent.

In certain embodiments, a formulation of the present invention comprises an excipient selected from the group consisting of cyclodextrins, celluloses, liposomes, micelle forming agents, e.g., bile acids, and polymeric carriers, e.g., polyesters and polyanhydrides; and a compound of the present invention. In certain embodiments, an aforementioned formulation renders orally bioavailable a compound of the present invention.

Methods of preparing these formulations or compositions include the step of bringing into association a compound of the present invention with the carrier and, optionally, one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association a compound of the present invention with liquid carriers, or finely divided solid carriers, or both, and then, if necessary, shaping the product.

Formulations of the invention suitable for oral administration may be in the form of capsules, cachets, pills, tablets, lozenges (using a flavored basis, usually sucrose and acacia or tragacanth), powders, granules, or as a solution or a suspension in an aqueous or non-aqueous liquid, or as an oil-in-water or water-in-oil liquid emulsion, or as an elixir or syrup, or as pastilles (using an inert base, such as gelatin and glycerin, or sucrose and acacia) and/or as mouth washes and the like, each containing a predetermined amount of a compound of the present invention as an active ingredient. A compound of the present invention may also be administered as a bolus, electuary or paste.

In solid dosage forms of the invention for oral administration (capsules, tablets, pills, dragees, powders, granules, troches and the like), the active ingredient is mixed with one or more pharmaceutically acceptable carriers, such as sodium citrate or dicalcium phosphate, and/or any of the following: (1) fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and/or silicic acid; (2) binders, such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; (3) humectants, such as glycerol; (4) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate; (5) solution retarding agents, such as paraffin; (6) absorption accelerators, such as quaternary ammonium compounds and surfactants, such as poloxamer and sodium lauryl sulfate; (7) wetting agents, such as, for example, cetyl alcohol, glycerol monostearate, and non-ionic surfactants; (8) absorbents, such as kaolin and bentonite clay; (9) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, zinc stearate, sodium stearate, stearic acid, and mixtures thereof; (10) coloring agents; and (11) controlled release agents such as crospovidone or ethyl cellulose. In the case of capsules, tablets and pills, the pharmaceutical compositions may also comprise buffering agents. Solid compositions of a similar type may also be employed as fillers in soft and hard shelled gelatin capsules using such excipients as lactose or milk sugars, as well as high molecular weight polyethylene glycols and the like.

A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared using binder (for example, gelatin or hydroxypropylmethyl cellulose), lubricant, inert diluent, preservative, disintegrant (for example, sodium starch glycolate or cross-linked sodium carboxymethyl cellulose), surface active or dispersing agent. Molded tablets may be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent.

The tablets, and other solid dosage forms of the pharmaceutical compositions of the present invention, such as dragees, capsules, pills and granules, may optionally be scored or prepared with coatings and shells, such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may also be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile, other polymer matrices, liposomes and/or microspheres. They may be formulated for rapid release, e.g., freeze-dried. They may be sterilized by, for example, filtration through a bacteria retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved in sterile water, or some other sterile injectable medium immediately before use. These compositions may also optionally contain opacifying agents and may be of a composition that they release the active ingredient(s) only, or preferentially, in a certain portion of the gastrointestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes. The active ingredient can also be in micro-encapsulated form, if appropriate, with one or more of the above described excipients.

Liquid dosage forms for oral administration of the compounds of the invention include pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active ingredient, the liquid dosage forms may contain inert diluents commonly used in the art, such as, for example, water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.

Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, coloring, perfuming and preservative agents.

Suspensions, in addition to the active compounds, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

Formulations of the pharmaceutical compositions of the invention for rectal or vaginal administration may be presented as a suppository, which may be prepared by mixing one or more compounds of the invention with one or more suitable nonirritating excipients or carriers comprising, for example, cocoa butter, polyethylene glycol, a suppository wax or a salicylate, and which is solid at room temperature, but liquid at body temperature and, therefore, will melt in the rectum or vaginal cavity and release the active compound.

Formulations of the present invention which are suitable for vaginal administration also include pessaries, tampons, creams, gels, pastes, foams or spray formulations containing such carriers as are known in the art to be appropriate.

Dosage forms for the topical or transdermal administration of a compound of this invention include powders, sprays, ointments, pastes, creams, lotions, gels, solutions, patches and inhalants. The active compound may be mixed under sterile conditions with a pharmaceutically acceptable carrier, and with any preservatives, buffers, or propellants which may be required.

The ointments, pastes, creams and gels may contain, in addition to an active compound of this invention, excipients, such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc and zinc oxide, or mixtures thereof.

Powders and sprays can contain, in addition to a compound of this invention, excipients such as lactose, talc, silicic acid, aluminum hydroxide, calcium silicates and polyamide powder, or mixtures of these substances. Sprays can additionally contain customary propellants, such as chlorofluorohydrocarbons and volatile unsubstituted hydrocarbons, such as butane and propane.

Transdermal patches have the added advantage of providing controlled delivery of a compound of the present invention to the body. Such dosage forms can be made by dissolving or dispersing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate of such flux can be controlled by either providing a rate controlling membrane or dispersing the compound in a polymer matrix or gel.

Ophthalmic formulations, eye ointments, powders, solutions and the like, are also contemplated as being within the scope of this invention.

Pharmaceutical compositions of this invention suitable for parenteral administration comprise one or more compounds of the invention in combination with one or more pharmaceutically acceptable sterile isotonic aqueous or non-aqueous solutions, dispersions, suspensions or emulsions, or sterile powders which may be reconstituted into sterile injectable solutions or dispersions just prior to use, which may contain sugars, alcohols, antioxidants, buffers, bacteriostats, solutes which render the formulation isotonic with the blood of the intended recipient or suspending or thickening agents.

Examples of suitable aqueous and non-aqueous carriers which may be employed in the pharmaceutical compositions of the invention include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and inj ectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

These compositions may also contain adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms upon the subject compounds may be ensured by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the compositions. In addition, prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents which delay absorption such as aluminum monostearate and gelatin.

In some cases, in order to prolong the effect of a drug, it is desirable to slow the absorption of the drug from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material having poor water solubility. The rate of absorption of the drug then depends upon its rate of dissolution which, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered drug form is accomplished by dissolving or suspending the drug in an oil vehicle.

Injectable depot forms are made by forming microencapsuled matrices of the subject compounds in biodegradable polymers such as polylactide-polyglycolide. Depending on the ratio of drug to polymer, and the nature of the particular polymer employed, the rate of drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissue.

When the compounds of the present invention are administered as pharmaceuticals, to humans and animals, they can be given per se or as a pharmaceutical composition containing, for example, 0.1 to 99% (more preferably, 10 to 30%) of active ingredient in combination with a pharmaceutically acceptable carrier.

Regardless of the route of administration selected, the compounds of the present invention, which may be used in a suitable hydrated form, and/or the pharmaceutical compositions of the present invention, are formulated into pharmaceutically acceptable dosage forms by conventional methods known to those of skill in the art.

Actual dosage levels of the active ingredients in the pharmaceutical compositions of this invention may be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular patient, composition, and mode of administration, without being toxic to the patient.

The selected dosage level will depend upon a variety of factors including the activity of the particular compound of the present invention employed, or the ester, salt or amide thereof, the route of administration, the time of administration, the rate of excretion or metabolism of the particular compound being employed, the rate and extent of absorption, the duration of the treatment, other drugs, compounds and/or materials used in combination with the particular compound employed, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.

A physician or veterinarian having ordinary skill in the art can readily determine and prescribe the effective amount of the pharmaceutical composition required. For example, the physician or veterinarian could start doses of the compounds of the invention employed in the pharmaceutical composition at levels lower than that required in order to achieve the desired therapeutic effect and gradually increase the dosage until the desired effect is achieved.

In general, a suitable daily dose of a compound of the invention will be that amount of the compound which is the lowest dose effective to produce a therapeutic effect. Such an effective dose will generally depend upon the factors described above. Generally, oral, intravenous, intracerebroventricular and subcutaneous doses of the compounds of this invention for a patient will range from about 0.01 to about 50 mg per kilogram of body weight per day.

If desired, the effective daily dose of the active compound may be administered as two, three, four, five, six or more sub-doses administered separately at appropriate intervals throughout the day, optionally, in unit dosage forms. In certain aspects of the invention, dosing is one administration per day.

While it is possible for a compound of the present invention to be administered alone, it is preferable to administer the compound as a pharmaceutical formulation (composition).

Definitions

Unless specifically stated otherwise herein, references made in the singular may also include the plural. For example, “a” and “an” may refer to either one, or one or more.

Unless otherwise indicated, any heteroatom with unsatisfied valences is assumed to have hydrogen atoms sufficient to satisfy the valences.

Throughout the specification and the appended claims, a given chemical formula or name shall encompass all stereo and optical isomers and racemates thereof where such isomers exist. Unless otherwise indicated, all chiral (enantiomeric and diastereomeric) and racemic forms are within the scope of the invention. Many geometric isomers of C═C double bonds, C═N double bonds, ring systems, and the like can also be present in the compounds, and all such stable isomers are contemplated in the present invention. Cis- and trans- (or E- and Z-) geometric isomers of the compounds of the present invention are described and may be isolated as a mixture of isomers or as separated isomeric forms. The present compounds can be isolated in optically active or racemic forms. Optically active forms may be prepared by resolution of racemic forms or by synthesis from optically active starting materials. All processes used to prepare compounds of the present invention and intermediates made therein are considered to be part of the present invention. When enantiomeric or diastereomeric products are prepared, they may be separated by conventional methods, for example, by chromatography or fractional crystallization. Depending on the process conditions the end products of the present invention are obtained either in free (neutral) or salt form. Both the free form and the salts of these end products are within the scope of the invention. If so desired, one form of a compound may be converted into another form. A free base or acid may be converted into a salt; a salt may be converted into the free compound or another salt; a mixture of isomeric compounds of the present invention may be separated into the individual isomers. Compounds of the present invention, free form and salts thereof, may exist in multiple tautomeric forms, in which hydrogen atoms are transposed to other parts of the molecules and the chemical bonds between the atoms of the molecules are consequently rearranged. It should be understood that all tautomeric forms, insofar as they may exist, are included within the invention.

When a substituent is noted as “optionally substituted”, the substituents are selected from, for example, substituents such as alkyl, cycloalkyl, aryl, heterocyclo, halo, hydroxy, alkoxy, oxo, alkanoyl, aryloxy, alkanoyloxy, amino, alkylamino, arylamino, arylalkylamino, disubstituted amines in which the 2 amino substituents are selected from alkyl, aryl or arylalkyl; alkanoylamino, aroylamino, aralkanoylamino, substituted alkanoylamino, substituted arylamino, substituted aralkanoylamino, thiol, alkylthio, arylthio, arylalkylthio, alkylthiono, arylthiono, arylalkylthiono, alkylsulfonyl, arylsulfonyl, arylalkylsulfonyl, sulfonamido, e.g. —SO₂NH₂, substituted sulfonamido, nitro, cyano, carboxy, carbamyl, e.g. —CONH₂, substituted carbamyl e.g. —CONHalkyl, —CONHaryl, —CONHarylalkyl or cases where there are two substituents on the nitrogen selected from alkyl, aryl or arylalkyl; alkoxycarbonyl, aryl, substituted aryl, guanidino, heterocyclyl, e.g., indolyl, imidazolyl, furyl, thienyl, thiazolyl, pyrrolidyl, pyridyl, pyrimidyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, homopiperazinyl and the like, and substituted heterocyclyl, unless otherwise defined.

For purposes of clarity and in accordance with standard convention in the art, the symbol

is used in formulas and tables to show the bond that is the point of attachment of the moiety or substituent to the core/nucleus of the structure.

Additionally, for purposes of clarity, where a substituent has a dash (-) that is not between two letters or symbols; this is used to indicate a point of attachment for a substituent. For example, —CONH₂ is attached through the carbon atom.

Additionally, for purposes of clarity, when there is no substituent shown at the end of a solid line, this indicates that there is a methyl (CH₃) group connected to the bond.

As used herein, the term “alkyl” or “alkylene” is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms. For example, “C₁-C₆ alkyl” denotes alkyl having 1 to 6 carbon atoms. Example alkyl groups include, but are not limited to, methyl (Me), ethyl (Et), propyl (e.g., n-propyl and isopropyl), butyl (e.g., n-butyl, isobutyl, t-butyl), and pentyl (e.g., n-pentyl, isopentyl, neopentyl).

The term “alkenyl” denotes a straight- or branch-chained hydrocarbon radical containing one or more double bonds and typically from 2 to 20 carbon atoms in length. For example, “C₂-C₈ alkenyl” contains from two to eight carbon atoms. Alkenyl groups include, but are not limited to, for example, ethenyl, propenyl, butenyl, 1-methyl-2-buten-1-yl, heptenyl, octenyl and the like.

The term “alkynyl” denotes a straight- or branch-chained hydrocarbon radical containing one or more triple bonds and typically from 2 to 20 carbon atoms in length.

For example, “C₂-C₈ alkenyl” contains from two to eight carbon atoms. Representative alkynyl groups include, but are not limited to, for example, ethynyl, 1-propynyl, 1-butynyl, heptynyl, octynyl and the like.

The term “alkoxy” or “alkyloxy” refers to an —O-alkyl group. “C₁₋₆ alkoxy” (or alkyloxy), is intended to include C₁, C₂, C₃, C₄, C₅, and C₆ alkoxy groups. Example alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy (e.g., n-propoxy and isopropoxy), and t-butoxy. Similarly, “alkylthio” or “thioalkoxy” represents an alkyl group as defined above with the indicated number of carbon atoms attached through a sulphur bridge; for example methyl-S- and ethyl-S-.

The term “aryl”, either alone or as part of a larger moiety such as “aralkyl”, “aralkoxy”, or aryloxyalkyl”, refers to monocyclic, bicyclic and tricyclic ring systems having a total of five to 15 ring members, wherein at least one ring in the system is aromatic and wherein each ring in the system contains three to seven ring members. In certain embodiments of the invention, “aryl” refers to an aromatic ring system which includes, but not limited to phenyl, biphenyl, indanyl, 1-naphthyl, 2-naphthyl and terahydronaphthyl. The term “aralkyl” or “arylalkyl” refers to an alkyl residue attached to an aryl ring. Non-limiting examples include benzyl, phenethyl and the like. The fused aryls may be connected to another group either at a suitable position on the cycloalkyl ring or the aromatic ring. For example:

Arrowed lines drawn from the ring system indicate that the bond may be attached to any of the suitable ring atoms.

The term “cycloalkyl” refers to cyclized alkyl groups. C₃₋₆ cycloalkyl is intended to include C₃, C₄, C₅, and C₆ cycloalkyl groups. Example cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and norbomyl. Branched cycloalkyl groups such as 1-methylcyclopropyl and 2-methylcyclopropyl are included in the definition of “cycloalkyl”. The term “cycloalkenyl” refers to cyclized alkenyl groups. C₄₋₆ cycloalkenyl is intended to include C₄, C₅, and C₆ cycloalkenyl groups. Example cycloalkenyl groups include, but are not limited to, cyclobutenyl, cyclopentenyl, and cyclohexenyl.

The term “cycloalkylalkyl” refers to a cycloalkyl or substituted cycloalkyl bonded to an alkyl group connected to the core of the compound.

“Halo” or “halogen” includes fluoro, chloro, bromo, and iodo. “Haloalkyl” is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms, substituted with 1 or more halogens. Examples ofhaloalkyl include, but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, trichloromethyl, pentafluoroethyl, pentachloroethyl, 2,2,2-trifluoroethyl, heptafluoropropyl, and heptachloropropyl. Examples of haloalkyl also include “fluoroalkyl” that is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms, substituted with 1 or more fluorine atoms.

“Haloalkoxy” or “haloalkyloxy” represents a haloalkyl group as defined above with the indicated number of carbon atoms attached through an oxygen bridge. For example, “C₁₋₆ haloalkoxy”, is intended to include C₁, C₂, C₃, C₄, C₅, and C₆ haloalkoxy groups. Examples of haloalkoxy include, but are not limited to, trifluoromethoxy, 2,2,2-trifluoroethoxy, and pentafluorothoxy. Similarly, “haloalkylthio” or “thiohaloalkoxy” represents a haloalkyl group as defined above with the indicated number of carbon atoms attached through a sulphur bridge; for example trifluoromethyl-S-, and pentafluoroethyl-S-.

The term “benzyl,” as used herein, refers to a methyl group on which one of the hydrogen atoms is replaced by a phenyl group.

As used herein, the term “heterocycle,” “heterocyclyl,” or “heterocyclic group” is intended to mean a stable 3-, 4-, 5-, 6-, or 7-membered monocyclic or bicyclic or 7-, 8-, 9-, 10-, 11-, 12-, 13-, or 14-membered polycyclic heterocyclic ring that is saturated, partially unsaturated, or fully unsaturated, and that contains carbon atoms and 1, 2, 3 or 4 heteroatoms independently selected from the group consisting of N, O and S; and including any polycyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The nitrogen and sulfur heteroatoms may optionally be oxidized (i.e., N→O and S(O)_(p), wherein p is 0, 1 or 2). The nitrogen atom may be substituted or unsubstituted (i.e., N or NR wherein R is H or another substituent, if defined). The heterocyclic ring may be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure. The heterocyclic rings described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. A nitrogen in the heterocycle may optionally be quatemized. It is preferred that when the total number of S and O atoms in the heterocycle exceeds 1, then these heteroatoms are not adjacent to one another. It is preferred that the total number of S and O atoms in the heterocycle is not more than 1. When the term “heterocycle” is used, it is intended to include heteroaryl.

Examples of heterocycles include, but are not limited to, acridinyl, azetidinyl, azocinyl, benzimidazolyl, benzofuranyl, benzothiofuranyl, benzothiophenyl, benzoxazolyl, benzoxazolinyl, benzthiazolyl, benztriazolyl, benztetrazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolinyl, carbazolyl, 4aH-carbazolyl, carbolinyl, chromanyl, chromenyl, cinnolinyl, decahydroquinolinyl, 2H,6H-1,5,2-dithiazinyl, dihydrofuro[2,3-b]tetrahydrofuran, furanyl, furazanyl, imidazolidinyl, imidazolinyl, imidazolyl, 1H-indazolyl, imidazolopyridinyl, indolenyl, indolinyl, indolizinyl, indolyl, 3H-indolyl, isatinoyl, isobenzofuranyl, isochromanyl, isoindazolyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiazolyl, isothiazolopyridinyl, isoxazolyl, isoxazolopyridinyl, methylenedioxyphenyl, morpholinyl, naphthyridinyl, octahydroisoquinolinyl, oxadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolidinyl, oxazolyl, oxazolopyridinyl, oxazolidinylperimidinyl, oxindolyl, pyrimidinyl, phenanthridinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl, phthalazinyl, piperazinyl, piperidinyl, piperidonyl, 4-piperidonyl, piperonyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolopyridinyl, pyrazolyl, pyridazinyl, pyridooxazolyl, pyridoimidazolyl, pyridothiazolyl, pyridinyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, 2-pyrrolidonyl, 2H-pyrrolyl, pyrrolyl, quinazolinyl, quinolinyl, 4H-quinolizinyl, quinoxalinyl, quinuclidinyl, tetrazolyl, tetrahydrofuranyl, tetrahydroisoquinolinyl, tetrahydroquinolinyl, 6H-1,2,5-thiadiazinyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, thianthrenyl, thiazolyl, thienyl, thiazolopyridinyl, thienothiazolyl, thienooxazolyl, thienoimidazolyl, thiophenyl, triazinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,5-triazolyl, 1,3,4-triazolyl, and xanthenyl. Also included are fused ring and spiro compounds containing, for example, the above heterocycles.

As used herein, the term “bicyclic heterocycle” or “bicyclic heterocyclic group” is intended to mean a stable 9- or 10-membered heterocyclic ring system which contains two fused rings and consists of carbon atoms and 1, 2, 3, or 4 heteroatoms independently selected from the group consisting of N, O and S. Of the two fused rings, one ring is a 5- or 6-membered monocyclic aromatic ring comprising a 5-membered heteroaryl ring, a 6-membered heteroaryl ring or a benzo ring, each fused to a second ring. The second ring is a 5- or 6-membered monocyclic ring which is saturated, partially unsaturated, or unsaturated, and comprises a 5-membered heterocycle, a 6-membered heterocycle or a carbocycle (provided the first ring is not benzo when the second ring is a carbocycle).

The bicyclic heterocyclic group may be attached to its pendant group at any heteroatom or carbon atom which results in a stable structure. The bicyclic heterocyclic group described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. It is preferred that when the total number of S and O atoms in the heterocycle exceeds 1, then these heteroatoms are not adjacent to one another. It is preferred that the total number of S and O atoms in the heterocycle is not more than 1.

Examples of a bicyclic heterocyclic group are, but not limited to, quinolinyl, isoquinolinyl, phthalazinyl, quinazolinyl, indolyl, isoindolyl, indolinyl, 1H-indazolyl, benzimidazolyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydroisoquinolinyl, 5,6,7,8-tetrahydro-quinolinyl, 2,3-dihydro-benzofuranyl, chromanyl, 1,2,3,4-tetrahydro-quinoxalinyl and 1,2,3,4-tetrahydro-quinazolinyl.

As used herein, the term “aromatic heterocyclic group” or “heteroaryl” is intended to mean stable monocyclic and polycyclic aromatic hydrocarbons that include at least one heteroatom ring member such as sulfur, oxygen, or nitrogen. Heteroaryl groups include, without limitation, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furyl, quinolyl, isoquinolyl, thienyl, imidazolyl, thiazolyl, indolyl, pyrroyl, oxazolyl, benzofuryl, benzothienyl, benzthiazolyl, isoxazolyl, pyrazolyl, triazolyl, tetrazolyl, indazolyl, 1,2,4-thiadiazolyl, isothiazolyl, purinyl, carbazolyl, benzimidazolyl, indolinyl, benzodioxolanyl and benzodioxane. Heteroaryl groups are substituted or unsubstituted. The nitrogen atom is substituted or unsubstituted (i.e., N or NR wherein R is H or another substituent, if defined). The nitrogen and sulfur heteroatoms may optionally be oxidized (i.e., N→O and S(O)_(p), wherein p is 0, 1 or 2).

Bridged rings are also included in the definition of heterocycle. A bridged ring occurs when one or more, preferably one to three, atoms (i.e., C, O, N, or S) link two non-adjacent carbon or nitrogen atoms. Examples of bridged rings include, but are not limited to, one carbon atom, two carbon atoms, one nitrogen atom, two nitrogen atoms, and a carbon-nitrogen group. It is noted that a bridge always converts a monocyclic ring into a tricyclic ring. When a ring is bridged, the substituents recited for the ring may also be present on the bridge.

The term “heterocyclylalkyl” refers to a heterocyclyl or substituted heterocyclyl bonded to an alkyl group connected to the core of the compound.

The term “counter ion” is used to represent a negatively charged species such as chloride, bromide, hydroxide, acetate, and sulfate or a positively charged species such as sodium (Na+), potassium (K+), ammonium (R_(n)NH_(m)+ where n=0-4 and m=0-4) and the like.

The term “electron withdrawing group” (EWG) refers to a substituent which polarizes a bond, drawing electron density towards itself and away from other bonded atoms. Examples of EWGs include, but are not limited to, CF₃, CF₂CF₃, CN, halogen, haloalkyl, NO₂, sulfone, sulfoxide, ester, sulfonamide, carboxamide, alkoxy, alkoxyether, alkenyl, alkynyl, OH, C(O)alkyl, CO₂H, phenyl, heteroaryl, —O-phenyl, and —O— heteroaryl. Preferred examples of EWG include, but are not limited to, CF₃, CF₂CF₃, CN, halogen, SO₂(C₁₋₄ alkyl), CONH(C₁₋₄ alkyl), CON(C₁₋₄ alkyl)₂, and heteroaryl. More preferred examples of EWG include, but are not limited to, CF₃ and CN.

As used herein, the term “amine protecting group” means any group known in the art of organic synthesis for the protection of amine groups which is stable to an ester reducing agent, a disubstituted hydrazine, R4-M and R7-M, a nucleophile, a hydrazine reducing agent, an activator, a strong base, a hindered amine base and a cyclizing agent. Such amine protecting groups fitting these criteria include those listed in Wuts, P. G. M. and Greene, T. W. Protecting Groups in Organic Synthesis, 4th Edition, Wiley (2007) and The Peptides: Analysis, Synthesis, Biology, Vol. 3, Academic Press, New York (1981), the disclosure of which is hereby incorporated by reference. Examples of amine protecting groups include, but are not limited to, the following: (1) acyl types such as formyl, trifluoroacetyl, phthalyl, and p-toluenesulfonyl; (2) aromatic carbamate types such as benzyloxycarbonyl (Cbz) and substituted benzyloxycarbonyls, 1-(p-biphenyl)-1-methylethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (Fmoc); (3) aliphatic carbamate types such as tert-butyloxycarbonyl (Boc), ethoxycarbonyl, diisopropylmethoxycarbonyl, and allyloxycarbonyl; (4) cyclic alkyl carbamate types such as cyclopentyloxycarbonyl and adamantyloxycarbonyl; (5) alkyl types such as triphenylmethyl and benzyl; (6) trialkylsilane such as trimethylsilane; (7) thiol containing types such as phenylthiocarbonyl and dithiasuccinoyl; and (8) alkyl types such as triphenylmethyl, methyl, and benzyl; and substituted alkyl types such as 2,2,2-trichloroethyl, 2-phenylethyl, and t-butyl; and trialkylsilane types such as trimethylsilane.

As referred to herein, the term “substituted” means that at least one hydrogen atom is replaced with a non-hydrogen group, provided that normal valencies are maintained and that the substitution results in a stable compound. Ring double bonds, as used herein, are double bonds that are formed between two adjacent ring atoms (e.g., C═C, C═N, or N═N).

In cases wherein there are nitrogen atoms (e.g., amines) on compounds of the present invention, these may be converted to N-oxides by treatment with an oxidizing agent (e.g., mCPBA and/or hydrogen peroxides) to afford other compounds of this invention. Thus, shown and claimed nitrogen atoms are considered to cover both the shown nitrogen and its N-oxide (N→O) derivative.

When any variable occurs more than one time in any constituent or formula for a compound, its definition at each occurrence is independent of its definition at every other occurrence. Thus, for example, if a group is shown to be substituted with 0-3 R, then said group may optionally be substituted with up to three R groups, and at each occurrence R is selected independently from the definition of R. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.

When a bond to a substituent is shown to cross a bond connecting two atoms in a ring, then such substituent may be bonded to any atom on the ring. When a substituent is listed without indicating the atom in which such substituent is bonded to the rest of the compound of a given formula, then such substituent may be bonded via any atom in such substituent. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.

As used herein, “pharmaceutically acceptable salts” refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic groups such as amines; and alkali or organic salts of acidic groups such as carboxylic acids. The pharmaceutically acceptable salts include the conventional non-toxic salts or the quatemary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, and nitric; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, and isethionic, and the like.

The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound that contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington: The Science and Practice of Pharmacy, 22^(nd) Edition, Allen, L. V. Jr., Ed.; Pharmaceutical Press, London, UK (2012), the disclosure of which is hereby incorporated by reference.

In addition, compounds of formula I may have prodrug forms. Any compound that will be converted in vivo to provide the bioactive agent (i.e., a compound of formula I) is a prodrug within the scope and spirit of the invention. Various forms of prodrugs are well known in the art. For examples of such prodrug derivatives, see:

a) Bundgaard, H., ed., Design of Prodrugs, Elsevier (1985), and Widder, K. et al., eds., Methods in Enzymology, 112:309-396, Academic Press (1985);

b) Bundgaard, H., Chapter 5, “Design and Application of Prodrugs,” A Textbook of Drug Design and Development, pp. 113-191, Krosgaard-Larsen, P. et al., eds., Harwood Academic Publishers (1991);

c) Bundgaard, H., Adv. Drug Deliv. Rev., 8:1-38 (1992);

d) Bundgaard, H. et al., J. Pharm. Sci., 77:285 (1988);

e) Kakeya, N. et al., Chem. Pharm. Bull., 32:692 (1984); and

f) Rautio, J (Editor). Prodrugs and Targeted Delivery (Methods and Principles in Medicinal Chemistry), Vol 47, Wiley-VCH, 2011.

Compounds containing a carboxy group can form physiologically hydrolyzable esters that serve as prodrugs by being hydrolyzed in the body to yield formula I compounds per se. Such prodrugs are preferably administered orally since hydrolysis in many instances occurs principally under the influence of the digestive enzymes. Parenteral administration may be used where the ester per se is active, or in those instances where hydrolysis occurs in the blood. Examples of physiologically hydrolyzable esters of compounds of formula I include C₁₋₆alkyl, C₁₋₆alkylbenzyl, 4-methoxybenzyl, indanyl, phthalyl, methoxymethyl, C₁₋₆ alkanoyloxy-C₁₋₆alkyl (e.g., acetoxymethyl, pivaloyloxymethyl or propionyloxymethyl), C₁₋₆alkoxycarbonyloxy-C₁₋₆alkyl (e.g., methoxycarbonyl-oxymethyl or ethoxycarbonyloxymethyl, glycyloxymethyl, phenylglycyloxymethyl, (5-methyl-2-oxo-1,3-dioxolen-4-yl)-methyl), and other well known physiologically hydrolyzable esters used, for example, in the penicillin and cephalosporin arts. Such esters may be prepared by conventional techniques known in the art.

Preparation of prodrugs is well known in the art and described in, for example, King, F. D., ed., Medicinal Chemistry: Principles and Practice, The Royal Society of Chemistry, Cambridge, UK (2^(nd) edition, reproduced, 2006); Testa, B. et al., Hydrolysis in Drug and Prodrug Metabolism. Chemistry, Biochemistry and Enzymology, VCHA and Wiley-VCH, Zurich, Switzerland (2003); Wermuth, C. G., ed., The Practice of Medicinal Chemistry, 3^(rd) edition, Academic Press, San Diego, Calif. (2008).

The present invention is intended to include all isotopes of atoms occurring in the present compounds. Isotopes include those atoms having the same atomic number but different mass numbers. By way of general example and without limitation, isotopes of hydrogen include deuterium and tritium. The isotopes of hydrogen can be denoted as ¹H (hydrogen), ²H (deuterium) and ³H (tritium). They are also commonly denoted as D for deuterium and T for tritium. In the application, CD₃ denotes a methyl group wherein all of the hydrogen atoms are deuterium. Isotopes of carbon include ¹³C and ¹⁴C. Isotopically-labeled compounds of the invention can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described herein, using an appropriate isotopically-labeled reagent in place of the non-labeled reagent otherwise employed.

The term “solvate” means a physical association of a compound of this invention with one or more solvent molecules, whether organic or inorganic. This physical association includes hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. The solvent molecules in the solvate may be present in a regular arrangement and/or a non-ordered arrangement. The solvate may comprise either a stoichiometric or nonstoichiometric amount of the solvent molecules. “Solvate” encompasses both solution-phase and isolable solvates. Exemplary solvates include, but are not limited to, hydrates, ethanolates, methanolates, and isopropanolates. Methods of solvation are generally known in the art.

As used herein, the term “patient” refers to organisms to be treated by the methods of the present invention. Such organisms preferably include, but are not limited to, mammals (e.g., murines, simians, equines, bovines, porcines, canines, felines, and the like), and most preferably refers to humans.

As used herein, the term “effective amount” means that amount of a drug or pharmaceutical agent, i.e., a compound of the invention, that will elicit the biological or medical response of a tissue, system, animal or human that is being sought, for instance, by a researcher or clinician. Furthermore, the term “therapeutically effective amount” means any amount which, as compared to a corresponding subject who has not received such amount, results in improved treatment, healing, prevention, or amelioration of a disease, disorder, or side effect, or a decrease in the rate of advancement of a disease or disorder. An effective amount can be administered in one or more administrations, applications or dosages and is not intended to be limited to a particular formulation or administration route. The term also includes within its scope amounts effective to enhance normal physiological function

As used herein, the term “treating” includes any effect, e.g., lessening, reducing, modulating, ameliorating or eliminating, that results in the improvement of the condition, disease, disorder, and the like, or ameliorating a symptom thereof.

As used herein, the term “pharmaceutical composition” refers to the combination of an active agent with a carrier, inert or active, making the composition especially suitable for diagnostic or therapeutic use in vivo or ex vivo.

Examples of bases include, but are not limited to, alkali metals (e.g., sodium) hydroxides, alkaline earth metals (e.g., magnesium), hydroxides, ammonia, and compounds of formula NW₄ ⁺, wherein W is C₁₋₄ alkyl, and the like.

For therapeutic use, salts of the compounds of the present invention are contemplated as being pharmaceutically acceptable. However, salts of acids and bases that are non-pharmaceutically acceptable may also find use, for example, in the preparation or purification of a pharmaceutically acceptable compound.

Methods of Preparation

The compounds of the present invention can be prepared in a number of ways well known to one skilled in the art of organic synthesis. The compounds of the present invention can be synthesized using the methods described below, together with synthetic methods known in the art of synthetic organic chemistry, or variations thereon as appreciated by those skilled in the art. Preferred methods include, but are not limited to, those described below. All references cited herein are hereby incorporated in their entirety by reference.

The compounds of this invention may be prepared using the reactions and techniques described in this section. The reactions are performed in solvents appropriate to the reagents and materials employed and are suitable for the transformations being affected. Also, in the description of the synthetic methods described below, it is to be understood that all proposed reaction conditions, including choice of solvent, reaction atmosphere, reaction temperature, duration of the experiment and work up procedures, are chosen to be the conditions standard for that reaction, which should be readily recognized by one skilled in the art. It is understood by one skilled in the art of organic synthesis that the functionality present on various portions of the molecule must be compatible with the reagents and reactions proposed. Such restrictions to the substituents that are compatible with the reaction conditions will be readily apparent to one skilled in the art and alternate methods must then be used. This will sometimes require a judgment to modify the order of the synthetic steps or to select one particular process scheme over another in order to obtain a desired compound of the invention. It will also be recognized that another major consideration in the planning of any synthetic route in this field is the judicious choice of the protecting group used for protection of the reactive functional groups present in the compounds described in this invention. An authoritative account describing the many alternatives to the trained practitioner is Greene and Wuts (Protective Groups In Organic Synthesis, Third Edition, Wiley and Sons, 1999).

Compounds of Formula (I) may be prepared by reference to the methods illustrated in the following Schemes. As shown therein the end product is a compound having the same structural formula as Formula (I). It will be understood that any compound of Formula (I) may be produced by the schemes by the suitable selection of reagents with appropriate substitution. Solvents, temperatures, pressures, and other reaction conditions may readily be selected by one of ordinary skill in the art. Starting materials are commercially available or readily prepared by one of ordinary skill in the art. Constituents of compounds are as defined herein or elsewhere in the specification.

The invention is further defined in the following Examples. It should be understood that the Examples are given by way of illustration only. From the above discussion and the Examples, one skilled in the art can ascertain the essential characteristics of the invention, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt the invention to various uses and conditions. As a result, the invention is not limited by the illustrative examples set forth herein below, but rather is defined by the claims appended hereto.

Analytical LC-MS/HPLC retention times reported for each example and intermediate using one of the following general analytical LC-MS/HPLC conditions below:

LC-MS Conditions:

Method A: Column: Waters Acquity UPLC BEH C18, 2.1×50 mm, 1.7 μm particle; Mobile Phase A: 5:95 acetonitrile:water with 0.1% TFA; Mobile Phase B: 95:5 acetonitrile:water with 0.1% TFA; Temperature: 50° C.; Gradient: 0-100% B over 3 minutes, then a 0.75 minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm. Method B: Column Waters Acquity UPLC BEH C18, 2.1×50 mm, 1.7 μm particle; Mobile Phase A: 5:95 acetonitrile:water with 10 mM NH₄OAc; Mobile Phase B: 95:5 acetonitrile:water with 10 mM NH₄OAc; Temperature: 50° C.; Gradient: 0-100% B over 3 minutes, then a 0.75 minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm. Method C: Column: Waters Acquity UPLC BEH C18, 2.1×50 mm, 1.7 m particle; Mobile Phase A: acetonitrile with 0.05% TFA; Mobile Phase B: water with 0.05% TFA; Temperature: 50° C.; Gradient: 2-98% B over 1.5 minutes, then a 0.1-minute hold at 100% B; Flow: 0.8 mL/min; Detection: UV at 220 nm. Method D: Column: Phenomenex LUNA C18, 30×2, 3 m particle; Mobile Phase A: 5:95 acetonitrile:water with 10 mM NH₄OAc; Mobile Phase B: 95:5 acetonitrile:water with 10 mM NH₄OAc; Temperature: 50° C.; Gradient: 0-100% B over 3 minutes, then a 0.75 minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm. Method E: Phenomenex Luna 2.0×50 mm 3 mm column; Mobile Phase A: 10:90 methanol:water with 0.1% TFA; Mobile Phase B: 90:10 methanol:water with 0.1% TFA; Temperature: 50° C.; Gradient: 0-100% B over 4 minutes, then a 1.0 minute hold at 100% B; flow rate 0.8 mL/min; Detection: UV at 220 nm. Method F: Column: Waters Acquity UPLC BEH C18 (2.1×50 mm), 1.7μ; Mobile phase A: 0.1% TFA in water; Mobile phase B: 0.1% TFA in acetonitrile; Gradient=20-90% B over 1.1 minute, then a 0.6 minute hold at 90% B; Temperature: 50° C.; Flow rate: 0.7 mL/min; Detection: UV at 220 nm. Method G: Column: Waters Acquity UPLC BEH C18 (2.1×50 mm) 1.7μ, Mobile phase A: 10 mM NH₄OAc:acetonitrile (95:5); Mobile phase B: 10 mM NH₄OAc:acetonitrile (5:95), Gradient=20-90% B over 1.1 minute, then a 0.6 minute hold at 90% B; Temperature: 50° C.; Flow rate: 0.7 mL/min; Detection: UV at 220 nm Method H: Column: Ascentis Express C18 (2.1×50 mm), 2.7μ; Mobile phase A: 10 mM NH₄OAc: acetonitrile (95:5), Mobile phase B: 10 mM NH₄OAc:acetonitrile (5:95), Gradient=0-100% B over 3 minutes; Temperature: 50° C.; Flow rate: 1.1 mL/min; Detection: UV at 220 nm. Method I: Column: Ascentis Express C18 (50×2.1) mm, 2.7μ; Mobile phase A: 0.1% TFA:acetonitrile (95:5), Mobile phase B: 0.1% TFA:acetonitrile (5:95), Gradient=0-100% B over 3 minutes; Temperature: 50° C.; Flow rate: 1.1 mL/min; Detection: UV at 220 nm. Method J: Column: Kinetex XB-C18 (75×3 mm) 2.6μ; Mobile phase A: 10 mM HCOONH₄: acetonitrile (98:2), Mobile phase B: 10 mM HCOONH₄:acetonitrile (2:98), Gradient=20-100% B over 4 minutes, then a 0.6 minute hold at 100% B; Temperature: 27° C.; Flow rate: 1.0 mL/min; Detection: UV at 220 nm. Method K: Column: ZORBAX-SBC18 (50×4.6 mm) 5μ; Mobile phase A: 10 mM HCOONH₄: acetonitrile (98:2), Mobile phase B: 10 mM HCOONH₄:acetonitrile (2:98), Gradient=20-100% B over 4 minutes, then a 0.6 minute hold at 100% B; Temperature: 27° C.; Flow rate: 1.5 mL/min; Detection: UV at 220 nm

Preparative HPLC Conditions:

Method L: Column: Waters X-Bridge C18, 19×150 mm, 5μ; Mobile Phase A: 0.1% TFA in water; Mobile Phase B: acetonitrile; Gradient: 10-100% B over 25 minutes, then a 5 minute hold at 100% B; Flow: 15 mL/min. Method M: Column: Inertsil ODS, 250×20 mm ID, 5μ; Mobile Phase A: 10 mM NH₄OAc in water; Mobile Phase B: Methanol; Gradient: 10-100% B over 25 minutes, then a 5 minute hold at 100% B; Flow: 17 mL/min. Method N: Column: Sunfire C18, 150×4.6 mm, 5μ; Mobile Phase A: 0.05% TFA in water; Mobile Phase B: acetonitrile; Gradient: 0-100% B over 18 minutes, then a 5 minute hold at 100% B; Flow: 1 mL/min. Method O: Column: Sunfire C18, 150×19 mm ID, 5μ; Mobile Phase A: 10 mM NH₄OAc in water; Mobile Phase B: acetonitrile; Gradient: 0-100% B over 18 minutes, then a 5 minute hold at 100% B; Flow: 17 mL/min.

Method P: Column: Waters X-Bridge C18, 19×150 mm, 5μ; Mobile Phase A: 10 mM NH₄OAc in water; Mobile Phase B: acetonitrile; Gradient: 0-100% B over 18 minutes, then a 5 minute hold at 100% B; Flow: 17 mL/min.

Method Q: Column: Symmetry C8, 300×19 mm ID, 7μ; Mobile Phase A: 10 mM NH₄OAc in water; Mobile Phase B: acetonitrile; Gradient: 0-100% B over 18 minutes, then a 5 minute hold at 100% B; Flow: 17 mL/min. Method R: Column: X-Bridge Phenyl, 250×19 mm ID, 5μ; Mobile Phase A: 10 mM NH₄OAc in water; Mobile Phase B: acetonitrile; Gradient: 0-100% B over 18 minutes, then a 5 minute hold at 100% B; Flow: 17 mL/min.

Abbreviations

The following abbreviations are used in the example section below and elsewhere herein

Ac acetyl aq. aqueous BisPin 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi-1,3,2- dioxaborolane o-DCB 1,2-dichlorobenzene DCM dichloromethane DIPEA or N,N-diisopropylethylamine Hunig's base DMF dimethyl formamide DMSO dimethylsulfoxide EtOAc ethyl acetate Et₃N or TEA triethylamine EtOH ethanol HPLC high-performance liquid chromatography MeOH methanol NBS N-bromosuccinamide NIS N-iodosuccinimide PdCl₂(dppf) [1,1′- Bis(diphenylphosphino)ferrocene]dichloropalladium(II) Pd(PPh₃)₄ tetrakis(triphenylphosphine)palladium(0) Ret. Time retention time RT room temperature satd. or sat'd saturated Xantphos 4,5-bis(diphenyl phosphino)-9,9-dimethylxanthene

Intermediate 1A: 2-(difluoromethyl)-6-(trimethylstannyl)pyridine

To a microwave vial were added 2-bromo-6-(difluoromethyl)pyridine (310 mg, 1.490 mmol), 1,1,1,2,2,2-hexamethyldistannane (CAS: 661-69-8, Sigma-Aldrich) (586 mg, 1.788 mmol) and 1,4-dioxane (6 mL). The reaction mixture was purged with nitrogen for 2 min. and Pd(Ph₃P)₄ (172 mg, 0.149 mmol) was added. The mixture was purged again with nitrogen and heated at 105° C. for 14 h. The reaction was then cooled to RT, passed through a pad of Celite® and washed with EtOAc. The filtrate was concentrated. The crude product was used for the next step. MS (ES): m/z=275.9 [M+H]⁺; HPLC Ret. Time 0.54 min. (HPLC Method C).

Intermediate 1B: 4,5-dibromo-1-(2,2-difluoroethyl)-1H-imidazole

To a solution of 4,5-dibromo-1H-imidazole (0.37 g, 1.64 mmol) in acetonitrile (15 mL) were added 1,1-difluoro-2-iodoethane (CAS-353-83-3, Sigma-Aldrich) (0.47 g, 2.46 mmol) and cesium carbonate (0.64 g, 1.97 mmol). The suspension was heated at 70° C. overnight, then allowed to cool to RT. The reaction mixture was passed through a pad of Celite® and washed with EtOAc. The filtrate was concentrated and the residue was purified by silica gel chromatography (80 g RediSep® column, eluting with a gradient from 10-65% EtOAc in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate 1B (0.34 g, 72% yield). MS (ES): m/z=288/290 [M+H]⁺; HPLC Ret. Time 0.68 min. (HPLC Method C); ¹H NMR (400 MHz, CDCl₃) δ ppm 7.61 (s, 1H), 6.00 (t, J=3.9 Hz, 1H), 4.36 (td, J=13.7, 3.9 Hz, 2H).

Intermediate 1C: 6-(4-bromo-1-(2,2-difluoroethyl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a vial were added Intermediate 1B (104 mg, 0.359 mmol), 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine (58.1 mg, 0.359 mmol) (reference: WO 2016/140884 A1), potassium carbonate (149 mg, 1.076 mmol), THF (3 mL), and water (1 mL). The reaction mixture was purged with nitrogen and Pd(Ph₃P)₄ (41.5 mg, 0.036 mmol) was added. The reaction mixture was heated at 70° C. for 2 days, cooled to RT, diluted with water, and extracted with DCM. The combined organic layer was washed with brine, dried over Na₂SO₄, filtered, and the filtrate was concentrated in vacuo. The crude product was purified by silica gel chromatography (24 g RediSep® column, eluting with a gradient from 10-80% B in DCM; B: 10% MeOH in DCM). Fractions containing the product were combined and evaporated to afford Intermediate 1C (65 mg, 55.4% yield). MS (ES): m/z=327/329 [M+H]⁺; HPLC Ret. Time 0.34 min. (HPLC Method C); ¹H NMR (400 MHz, CDCl₃) d ppm 8.33-8.18 (m, 1H), 7.81-7.66 (m, 3H), 7.63 (s, 1H), 7.07 (dd, J=9.3, 1.8 Hz, 1H), 5.90 (t, J=3.3 Hz, 1H), 4.27 (td, J=14.7, 3.3 Hz, 2H).

Example 1: 6-(1-(2,2-difluoroethyl)-4-(6-(difluoromethyl)pyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a vial were added Intermediates 1A (20 mg, 0.061 mmol), 1C (26.8 mg, 0.092 mmol), and 1,4-dioxane (2 mL). The reaction mixture was purged with nitrogen for 2 min. and Pd(Ph₃P)₄ (7.06 mg, 6.11 μmol) was added. The reaction mixture was purged again with nitrogen for 2 min. and heated at 105° C. for 6 h. The dark reaction mixture was cooled to RT, passed through a pad of Celite®, and washed with DCM. The filtrate was concentrated and the resulting residue was dissolved in a DMF-MeOH and purified via preparative HPLC. Fractions containing the desired product were combined and dried under vacuum to afford Example 1 (4.4 mg, 19% yield). MS (ES): m/z=375.9 [M+H]⁺; HPLC Ret. Time 1.354 and 1.783 min. (HPLC Methods A and B, respectively); ¹H NMR (500 MHz, DMSO-d₆) d 8.70 (s, 1H), 8.07-7.90 (m, 4H), 7.71-7.54 (m, 2H), 7.44 (d, J=7.3 Hz, 1H), 7.20 (dd, J=9.2, 1.8 Hz, 1H), 6.53-6.15 (m, 2H), 4.59-4.43 (m, 2H).

Examples shown in Table 1 have been prepared in a manner similar to Example 1 using Intermediate 1B and the corresponding tin reagents prepared in a manner similar to Intermediate 1A from the corresponding bromide.

TABLE 1 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 2

6-(1-(2,2- difluoroethyl)-4- (pyridin-2-yl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine 326.0 0.963 1.899 A B 3

6-(1-(2,2- difluoroethyl)-4-(5- fluoro-6- methylpyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridine 358.0 1.779 1.200 A B 4

6-(1-(2,2- difluoroethyl)-4-(5- fluoropyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridine 344.0 0.844 1.178 A B

Intermediate 5A: 6-(4-bromo-1-(2,2-difluoroethyl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carbonitrile

To a pressure bottle were added Intermediate 1B (420 mg, 1.449 mmol), 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile (271 mg, 1.449 mmol) (reference: WO 2014/055955 A1), potassium carbonate (601 mg, 4.35 mmol), THF (12 mL) and water (4 mL). The reaction mixture was purged with nitrogen and Pd(Ph₃P)₄ (167 mg, 0.145 mmol) was added. The mixture was purged again with nitrogen and heated at 70° C. for 36 h. It was then cooled to RT and diluted with DCM and water. The layers were separated and the aqueous layer was extracted with DCM. The combined organic layer was washed with brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. The crude product was purified by silica gel chromatography (40 g RediSep® column, eluting with a gradient from 40-100% EtOAc in DCM, the 50-100% B in DCM, B: 10% MeOH in DCM)). Fractions containing the product were combined and evaporated to afford Intermediate 5A (220 mg, 43.1% yield). MS (ES): m/z=353.9 [M+H]⁺; HPLC Ret. Time 0.68 min. (HPLC Method C); ¹H NMR (400 MHz, CDCl₃) d ppm 8.50-8.40 (m, 1H), 8.28 (s, 1H), 7.97-7.87 (m, 1H), 7.70 (s, 1H), 7.43 (dd, J=9.3, 1.5 Hz, 1H), 5.95 (t, J=3.0 Hz, 1H), 4.30 (td, J=14.8, 3.0 Hz, 2H).

Example 5: 6-(1-(2,2-difluoroethyl)-4-(6-(difluoromethyl)pyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carbonitrile

To a vial were added Intermediates 5A (62 mg, 0.176 mmol), 1A (51.4 mg, 0.176 mmol), and 1,4-dioxane (2 mL). The reaction mixture was purged with nitrogen for 2 min. and then Pd(Ph₃P)₄ (20.35 mg, 0.018 mmol) was added. The reaction mixture was heated at 105° C. overnight. The dark reaction mixture was cooled to RT, passed through a pad of Celite® and the filter-cake washed with DCM. The combined filtrate was concentrated. The crude product was dissolved in a mixture of DMF and methanol, and purified by preparative HPLC. Fractions containing the desired product were combined and dried under vacuum to afford Example 5 (44.4 mg, 63% yield). MS (ES): m/z=401.0 [M+H]⁺; HPLC Ret. Time 1.197 min. and 1.412 min. (HPLC Methods A and B, respectively); ¹H NMR (500 MHz, DMSO-d₆) d ppm 8.76 (s, 1H), 8.51 (s, 1H), 8.16-8.02 (m, 2H), 7.98 (t, J=7.7 Hz, 1H), 7.92-7.80 (m, 1H), 7.58 (dd, J=9.2, 1.5 Hz, 1H), 7.44 (d, J=7.3 Hz, 1H), 6.58-6.14 (m, 2H), 6.25 (t, J=3.1 Hz, 1H), 4.55 (td, J=16.0, 2.9 Hz, 2H).

Examples shown in Table 2 have been prepared in a manner similar to Example 5 using Intermediate 5A and the corresponding tin reagents prepared in a manner similar to Intermediate 1A from the corresponding bromide.

TABLE 2 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 6

6-(1-(2,2- difluoroethyl)-4- (pyridin-2-yl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 351.0 1.178 1.447 A B 7

6-(1-(2,2- difluoroethyl)-4-(5- fluoro-6- methylpyridin-2- yl)-1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 383.0 1.440 1.616 A B 8

6-(1-(2,2- difluoroethyl)-4-(5- fluoropyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 369.0 1.098 1.336 A B 9

6-(4-(6- cyclopropylpyridin- 2-yl)-1-(2,2- difluoroethyl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 490.9 1.136 1.568 A B

Example 10: 6-(1-(2,2-difluoroethyl)-4-(6-(difluoromethyl)pyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carboxamide

To a vial were added TFA (0.069 mL, 0.899 mmol) and sulfuric acid (0.016 mL, 0.300 mmol). The mixture was stirred at RT for 10 min. A solution of compound 5 (30 mg, 0.075 mmol) in TFA (0.069 mL, 0.899 mmol) was added. The reaction mixture was heated at 85° C. for 2 h, cooled to RT and concentrated. The resulting residue was diluted with DCM and neutralized with sat'd aq. solution of NaHCO₃. The layers were separated and the aqueous layer was extracted with DCM. The combined organic layer was washed with brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. The crude product was dissolved in a mixture of DMF and methanol, and purified by preparative HPLC. Fractions containing the desired product were combined and dried under vacuum to afford Example 10 (9.9 mg, 32% yield). MS (ES): m/z=419.0 [M+H]⁺; HPLC Ret. Time 0.937 min. and 1.148 min. (HPLC Methods A and B, respectively); ¹H NMR (500 MHz, DMSO-d₆) d ppm 9.63 (s, 1H), 8.39 (s, 1H), 8.08-7.91 (m, 4H), 7.74 (d, J=9.2 Hz, 1H), 7.53-7.39 (m, 2H), 6.52-6.16 (m, 2H), 4.57-4.41 (m, 2H).

Examples shown in Table 3 have been prepared in a manner similar to Example 10 from the corresponding cyano compound.

TABLE 3 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 11

6-(1-(2,2- difluoroethyl)-4- (pyridin-2-yl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 369.0 0.883 1.831 A B 12

6-(1-(2,2- difluoroethyl)-4-(5- fluoro-6- methylpyridin-2- yl)-1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 401.1 0.952 1.215 A B 13

6-(1-(2,2- difluoroethyl)-4-(5- fluoropyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 387.0 0.890 1.090 A B 14

6-(4-(6- cyclopropylpyridin- 2-yl)-1-(2,2- difluoroethyl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 409.0 0.911 1.256 A B

Intermediate 15A: 2-bromo-1-(6-methylpyridin-2-yl)ethanone, hydrobromide

To an ice-cold solution of 1-(6-methylpyridin-2-yl)ethanone (8.7 g, 64.4 mmol) and hydrobromic acid (23.31 mL, 129 mmol, 33% solution in AcOH) in DCM (100 mL) was added bromine (3.32 mL, 64.4 mmol) and the reaction mixture was stirred at RT for 3 h. Soon a solid precipitated out that was filtered off and the filter-cake was washed several times with DCM. The yellow solid was air-dried to obtain intermediate 15A (18.0 g, 95% yield) as a bright yellow solid. ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.01-7.93 (m, 1H), 7.88 (s, 1H), 7.62 (d, J=7.8 Hz, 1H), 5.03 (s, 2H), 2.59 (s, 3H).

Intermediate 15B: 2-(1H-imidazol-4-yl)-6-methylpyridine

A solution of Intermediate 15A (31.2 g, 106 mmol) in neat formamide (33.7 mL, 846 mmol) was heated in an oil-bath at 170° C. for 5 h. The reaction mixture was then filtered off hot and the filtrate was subjected to vacuum distillation to remove formamide. The dark residue was then basified to pH˜8 with satd. aq. NaHCO₃ solution and extracted with EtOAc (3×125 mL). The combined organic layer was washed with water (3×50 mL) and brine, dried over anhydrous MgSO₄, filtered and the filtrate concentrated under reduced pressure. The crude product was purified by silica gel chromatography (220 g RediSep® column, eluting with a gradient of 0-10% MeOH in EtOAc). Fractions containing the product were combined and evaporated to afford Intermediate 15B (3.37 g, 20% yield) as a dark oil. MS (ES): m/z=160.1 [M+H]⁺.

Conditions for N-1 alkylation of Intermediate 15B: Condition A. To a solution of Intermediate 15B (1 equivalent) in acetonitrile was added Cs₂CO₃ (1.5 equivalents) and the reaction mixture was stirred at RT for 15 min. Then the alkyl halide (2.0 equivalent) was added to the reaction and the resultant mixture was heated in an oil-bath at 50° C. for 16 h. The reaction mixture was then cooled to RT, filtered off and the filtrate concentrated under reduced pressure. The residue was suspended in DCM and again filtered off. The filtrate was evaporation under reduced pressure. The residue was purified by silica gel chromatography. Fractions containing the product were combined and evaporated to afford the corresponding N-1 alkylated intermediate. Condition B. To a solution of Intermediate 15B (1 equivalent) in DMSO was added Cs₂CO₃ (1.05 equivalent) and alkyl triflate (1.5 equivalent) at RT and the reaction mixture continued stirring at RT for 4 h. The reaction mixture was then diluted with water and extracted thrice with EtOAc. The combined organic layer was washed with water and brine, dried over anhydrous MgSO₄, filtered and the filtrate evaporated under reduced pressure. The residue was purified by silica gel chromatography. Fractions containing the product were combined and evaporated to afford the corresponding N-1 alkylated intermediate.

Intermediate 15C: 2-(1-(2,2-difluoroethyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 15C was synthesized according to alkylation condition A by reacting intermediate 15B with 1,1-difluoro-2-iodoethane. The crude product was purified by silica gel chromatography (80 g RediSep® column, eluting with a gradient of 0-100% EtOAc in DCM). Fractions containing the product were combined and evaporated to afford Intermediate 15C (0.3 g, 42.1% yield) as a pale yellow solid. MS (ES): m/z=224.1 [M+H]⁺; ¹H NMR (400 MHz, Methanol-d₄) d ppm 7.80 (d, J=2.3 Hz, 2H), 7.75-7.68 (m, 2H), 7.19-7.09 (m, 1H), 4.57 (td, J=15.3, 3.3 Hz, 2H), 2.56 (s, 3H).

Intermediate 15D: 2-(5-bromo-1-(2,2-difluoroethyl)-1H-imidazol-4-yl)-6-methylpyridine

To a solution of Intermediate 15D (0.3 g, 1.344 mmol) in DCM (7.17 mL) and MeOH (1.8 mL) was added NBS (0.251 g, 1.41 mmol) and the reaction mixture was stirred at RT for 1 h. It was then concentrated under reduced pressure to afford a solid. The crude product was purified by silica gel chromatography (40 g RediSep® column, eluting with a gradient of 0-5% MeOH in EtOAc). Fractions containing the product were combined and evaporated to afford Intermediate 15D (0.18 g, 43.1% yield) as a white solid. MS (ES): m/z=303.9 [M+H]⁺.

Intermediate 16A: 2-(1-(2-fluoroethyl)-1H-imidazol-4-yl)-6-methylpyridine, TFA

Intermediate 16A was synthesized according to alkylation condition A by reacting intermediate 15B with 1-fluoro-2-iodoethane. The crude product was purified by preparative HPLC. Fractions containing the product were combined and evaporated to afford Intermediate 17A (0.288 g, 52.4% yield) as a TFA salt. MS (ES): m/z=206.1 [M+H]⁺.

Intermediate 16B: 2-(5-bromo-1-(2-fluoroethyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 16B was synthesized analogous to intermediate 15B by reacting intermediate 16A with NBS. The crude product was purified by silica gel chromatography (80 g RediSep® column, eluting with a gradient of 10-90% DCM in EtOAc). Fractions containing the product were combined and evaporated to afford Intermediate 16B (0.075 g, 29.3% yield). MS (ES): m/z=284.0 [M+H]⁺.

Intermediate 17A: 2-(1-(3-fluoropropyl)-1H-imidazol-4-yl)-6-methylpyridine, TFA

Intermediate 17A was synthesized according to alkylation condition A by reacting intermediate 15B with 1-fluoro-3-iodopropane. The crude product was purified by preparative LC/MS. Fractions containing the product were combined and evaporated to afford Intermediate 17A (0.758 g, 53.2% yield) as the TFA salt. MS (ES): m/z=220.1 [M+H]⁺.

Intermediate 17B: 2-(5-bromo-1-(3-fluoropropyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 17B was synthesized analogous to intermediate 15B by reacting intermediate 17A with NBS. The crude product was purified by silica gel chromatography (80 g RediSep® column, eluting with a gradient of 10-90% DCM in EtOAc). Fractions containing the product were combined and evaporated to afford Intermediate 17B (0.302 g, 44.5% yield) as a white solid. MS (ES): m/z=298 [M+H]⁺.

Intermediate 18A: 2-methyl-6-(1-(4,4,4-trifluorobutyl)-1H-imidazol-4-yl)pyridine, TFA

Intermediate 18A was synthesized according to alkylation condition B by reacting intermediate 15B with 4,4,4-trifluorobutyl trifluoromethanesulfonate. The crude product was purified by preparative LC/MS. Fractions containing the product were combined and evaporated to afford Intermediate 18A (1.035 g, 59.0% yield) as the TFA salt. MS (ES): m/z=270.15 [M+H]⁺.

Intermediate 18B: 2-(5-bromo-1-(4,4,4-trifluorobutyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 18B was synthesized analogous to intermediate 15B by reacting intermediate 18A with NBS. The crude product was purified by silica gel chromatography (80 g RediSep® column, eluting with a gradient of 0-80% EtOAc in DCM). Fractions containing the product were combined and evaporated to afford Intermediate 18B (0.51 g, 54.1% yield) as a pale yellow syrup. MS (ES): m/z=350.1 [M+2H]⁺.

Example 15: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carbonitrile

To a degassed solution of Intermediate 15B (0.09 g, 0.295 mmol) and 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile (reference: WO 2014/055955 A1) (0.139 g, 0.516 mmol) in 2M aq. solution of K₃PO₄ (0.44 mL, 0.884 mmol) and 1,4-dioxane (2.95 mL) was added Pd(Ph₃P)₄ (0.034 g, 0.029 mmol). The reaction mixture was degassed again for 2 min. and then the sealed tube was heated in an oil-bath at 100° C. for 12 h. The solvent was then evaporated under reduced pressure to afford a residue that was suspended in water and extracted with a solution of 5% MeOH in DCM (3×5 mL). The combined organic layer was washed with brine, dried over anhydrous MgSO₄, filtered and the filtrate concentrated under reduced pressure. The crude product was purified by silica gel chromatography (40 g RediSep® column, eluting with a gradient of 2-5% MeOH in EtOAc). Fractions containing the product were combined and evaporated to afford Intermediate 15 (0.035 g, 32.6% yield). MS (ES): m/z=365.0 [M+H]⁺; ¹H NMR (500 MHz, DMSO-d₆) d ppm 8.83 (s, 1H), 8.53 (s, 1H), 7.99 (s, 1H), 7.88 (d, J=9.2 Hz, 1H), 7.73 (d, J=8.1 Hz, 1H), 7.70-7.55 (m, 2H), 7.02 (d, J=7.7 Hz, 1H), 4.62-4.47 (m, 2H), 2.11 (s, 3H).

The examples described in Table 4 were synthesized analogous to Example 15 by a Suzuki coupling reaction between 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile and the corresponding bromides.

TABLE 4 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 16

6-(1-(2-fluoroethyl)-4- (6-methylpyridin-2- yl)-1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 347.2 0.92 1.29 A B 17

6-(1-(3-fluoropropyl)- 4-(6-methylpyridin-2- yl)-1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 361.2 0.93 1.38 A B 18

6-(4-(6-methylpyridin- 2-yl)-1-(4,4,4- trifluorobutyl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carbonitrile 411.2 1.12 1.58 A B

Example 19: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carboxamide

A solution of TFA (0.07 mL, 0.862 mmol) and conc. H₂SO₄ (0.017 mL, 0.314 mmol) was stirred at RT for 15 min. To this mixture was added a solution of compound 15 (0.025 g, 0.069 mmol) in TFA (0.5 mL). The resultant reaction mixture was heated in an oil-bath at 85° C. for 2 h and then the volatiles were evaporated under reduced pressure. The residue was basified with satd. aq. NaHCO₃ solution and extracted with a solution of 5% MeOH in DCM (2×5 mL). The combined organic layer was washed with brine, dried over anhydrous MgSO₄, filtered and the filtrate concentrated under reduced pressure. The crude product was purified via preparative LC/MS. Fractions containing the desired product were combined and evaporated to afford compound 19 (9.0 mg, 34.3% yield). MS (ES), m/z=383.0 [M+H]⁺; HPLC Ret. Time 1.03 min. and 2.14 min. (HPLC Methods A and B, respectively); ¹H NMR (500 MHz, DMSO-d₆) d ppm 9.61 (s, 1H), 8.39 (s, 1H), 7.96 (s, 1H), 7.78-7.67 (m, 2H), 7.67-7.59 (m, 1H), 7.44 (dd, J=9.2, 1.5 Hz, 1H), 6.98 (d, J=7.3 Hz, 1H), 4.56-4.36 (m, 2H), 2.04 (s, 3H).

The examples described in Table 5 were synthesized analogous to Example 19 by heating the cyano intermediate with TFA-H₂SO₄.

TABLE 5 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 20

6-(1-(2-fluoroethyl)-4- (6-methylpyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 365.2 0.96 2.01 A B 21

6-(1-(3-fluoropropyl)- 4-(6-methylpyridin-2- yl)-1H-imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 379.2 0.93 1.39 A B 22

6-(4-(6-methylpyridin- 2-yl)-1-(4,4,4- trifluorobutyl)-1H- imidazol-5- yl)imidazo[1,2- a]pyridine-3- carboxamide 429.2 0.89 1.30 A B

Example 23: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a solution of Intermediate 15D (1.4 g, 4.63 mmol) and imidazo[1,2-a]pyridin-6-ylboronic acid (1.126 g, 6.95 mmol) in 1,4-dioxane (40 mL) was added K₃PO₄ (6.95 mL, 13.90 mmol) and the solution was purged with argon for 2 min. and Pd(Ph₃P)₄ (0.535 g, 0.463 mmol) was added. The reaction mixture was heated at 100° C. for 16 h, cooled to RT and concentrated in vacuo. The resulting residue was purified by preparative HPLC (Method Q). Fractions containing the product were combined and evaporated to afford Intermediate 23 (180 mg, 11.45% yield). MS (ES): m/z=340.2 [M+H]⁺; HPLC Ret. Time 1.29 min. (HPLC Method J).

Example 24: 3-chloro-6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a solution of compound 23 (40 mg, 0.118 mmol) in DMF (1 mL) was added NCS (15.74 mg, 0.118 mmol). The reaction mixture was stirred at RT overnight and then diluted with EtOAc and water. The layers were separated and the aqueous layer was extracted with EtOAc. The combined organic layer was washed with brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method J). Fractions containing the desired product were combined and dried under vacuum to afford Example 24 (17.6 mg, 39.9% yield). MS (ES): m/z=374.1 [M+H]⁺; HPLC Ret. Time 1.59 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.53 (dd, J=2.0, 1.0 Hz, 1H), 7.98 (s, 1H), 7.82-7.76 (m, 1H), 7.74-7.60 (m, 3H), 7.33 (dd, J=9.3, 1.8 Hz, 1H), 7.01 (d, J=7.5 Hz, 1H), 6.43-6.09 (m, 1H), 4.50 (td, J=16.1, 3.0 Hz, 2H), 2.14-2.07 (m, 3H).

Example 25: 5-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)-1H-indazole

Example 25 was synthesized analogous to Example 23 (Scheme 4) by treating intermediate 15D with (1H-indazol-5-yl)boronic acid. The crude product was purified by preparative HPLC (Method P). Fractions containing the desired product were combined and evaporated to afford Example 25 (1 mg, 1% yield). MS (ES): m/z=340.1 [M+H]⁺; HPLC Ret. Time 1.18 min. (HPLC Method C); ¹H NMR (400 MHz, DMSO-d6): δ ppm 13.1 (bs, 1H), 8.10 (s, 1H), 7.87 (s, 1H), 7.79 (s, 1H), 7.63-7.47 (m, 3H), 7.32 (d, J=12.00 Hz, 1H), 6.93 (d, J=8.00 Hz, 1H), 6.30-6.01 (m, 1H), 4.39-4.30 (m, 2H), 2.09 (s, 3H).

Intermediate 26A: 3-bromo-6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a solution of Intermediate 23 (160 mg, 0.472 mmol) in DMF (5 mL) was added NBS (84 mg, 0.472 mmol) at 0° C. The reaction mixture was stirred at RT for 1 h and diluted with EtOAc. The organic layer was washed with water and brine, dried over Na₂SO₄, filtered and the filtrate concentrated in vacuo to afford Intermediate 26A (120 mg, 60.9% yield). MS (ES): m/z=418.4 [M+H]⁺; HPLC Ret. Time 1.06 min. (HPLC Method G).

Example 26: 3-cyclopropyl-6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine

To a solution of Intermediate 26A (60 mg, 0.143 mmol) in 1,4-dioxane (1 mL) was added cyclopropylboronic acid (18.48 mg, 0.215 mmol) and K₂CO₃ (59.5 mg, 0.430 mmol). The solution was purged with argon for 2 min. and PdCl₂(dppf)-CH₂Cl₂ adduct (11.72 mg, 0.014 mmol) was added. The reaction mixture was heated at 100° C. for 16 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method L). Fractions containing the desired product were combined and dried under vacuum to afford Example 26 (22 mg, 39.6% yield). MS (ES): m/z=380.1 [M+H]⁺; HPLC Ret. Time 1.55 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.57-8.51 (m, 1H), 7.96 (s, 1H), 7.72-7.61 (m, 2H), 7.56 (dd, J=9.5, 1.0 Hz, 1H), 7.39-7.36 (m, 1H), 7.25-7.19 (m, 1H), 7.03-6.97 (m, 1H), 6.43-6.09 (m, 1H), 4.49 (td, J=16.1, 3.0 Hz, 2H), 2.11 (s, 3H), 2.04-1.95 (m, 1H), 1.02-0.94 (m, 2H), 0.71-0.64 (m, 2H).

The example shown in Table 6 has been prepared analogous to Example 26, using intermediate 26A and methylboronic acid.

TABLE 6 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 27

6-(1-(2,2-difluoroethyl)-4- (6-methylpyridin-2-yl)-1H- imidazol-5-yl)-3- methylimidazo[1,2- a]pyridine 354.1 1.364 H

Example 28: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)-N-(diphenylmethylene)imidazo[1,2-a]pyridin-3-amine

To a solution of Intermediate 26A (60 mg, 0.143 mmol) in 1,4-dioxane (5 mL) was added benzophenone imine (0.040 mL, 0.239 mmol), Cs₂CO₃ (156 mg, 0.478 mmol) and Xantphos (27.7 mg, 0.048 mmol). The solution was purged with Argon for 2 min. and Pd₂(dba)₃ (43.8 mg, 0.048 mmol) was added. The reaction mixture was heated at 100° C. for 16 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method L). Fractions containing the desired product were combined and dried under vacuum to afford Example 28 (60 mg, 48.4% yield). MS (ES): m/z=519.2 [M+H]⁺; HPLC Ret. Time 2.24 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 9.02 (dd, J=0.98, 1.71 Hz, 1H), 8.00 (s, 1H), 7.76-7.84 (m, 2H), 7.60-7.73 (m, 5H), 7.53 (dd, J=0.86, 9.17 Hz, 1H), 7.38-7.48 (m, 3H), 7.27-7.37 (m, 3H), 6.99 (d, J=7.09 Hz, 1H), 6.10-6.47 (m, 1H), 5.83 (s, 1H), 4.51 (dt, J=2.45, 16.02 Hz, 2H), 2.09 (s, 3H).

Intermediate 29A: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)-3-nitroimidazo[1,2-a]pyridine

Concentrated H₂SO₄ (0.5 mL, 9.38 mmol) was cooled to 5° C. and Compound 23 (50 mg, 0.147 mmol) was added portion wise, followed by a dropwise addition of HNO₃ (0.05 mL, 1.119 mmol). The reaction mixture was stirred at RT for 1 h, quenched with ice/water, and made basic using 10% aq. solution of NaHCO₃. The aqueous phase was extracted with EtOAc. The organic layer was washed with water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo to afford Intermediate 29A (50 mg, 88% yield). MS (ES): m/z=385.4 [M+H]⁺; HPLC Ret. Time 1.03 min. (HPLC Method G).

Example 29: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-amine

To a solution of Intermediate 29A (30 mg, 0.078 mmol) in EtOH (0.6 mL)/THF (0.4 mL)/water (0.2 mL) was added ammonium chloride (62.6 mg, 1.171 mmol), followed by zinc (77 mg, 1.171 mmol) at 0° C. The reaction mixture was stirred at RT for 1 h, filtered and the filtrate concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method Q). Fractions containing the desired product were combined and dried under vacuum to afford Example 29 (2.5 mg, 9.04% yield). MS (ES): m/z=355.2 [M+H]⁺; HPLC Ret. Time 1.045. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.19 (s, 1H), 7.96 (br. s., 1H), 7.62 (d, J=6.36 Hz, 2H), 7.41 (d, J=9.05 Hz, 1H), 6.84-7.05 (m, 3H), 6.05-6.43 (m, 1H), 5.04 (br. s., 2H), 4.40-4.55 (m, 2H), 1.90 (s, 3H).

Example 30: 2-chloro-6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-amine

To a solution of Intermediate 29A (100 mg, 0.260 mmol) in HCl (1.1 mL, 36.2 mmol) was added tin(II) chloride (74.0 mg, 0.390 mmol) at 0° C. The reaction mixture was stirred at RT for 1 h, filtered and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 30 (5 mg, 4.70% yield). MS (ES): m/z=389.1 [M+H]⁺; HPLC Ret. Time 1.245 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.23 (d, J=1.00 Hz, 1H), 7.94 (s, 1H), 7.56-7.70 (m, 2H), 7.35-7.41 (m, 1H), 6.96-7.07 (m, 2H), 6.05-6.40 (m, 1H), 5.08 (s, 2H), 4.48 (dt, J=3.01, 16.06 Hz, 2H), 2.09-2.17 (m, 3H).

Example 31: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)-3-fluoroimidazo[1,2-a]pyridine

To a solution of Intermediate 15D (60 mg, 0.199 mmol)) in 1,4-dioxane (3 mL) was added 3-fluoro-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine (78 mg, 0.298 mmol) and K₂CO₃ (0.298 mL, 0.596 mmol). The solution was purged with argon for 2 min. and PdCl₂(dppf)-CH₂Cl₂ adduct (16.22 mg, 0.020 mmol) was added. The reaction mixture was heated at 100° C. for 16 h, then cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method O). Fractions containing the desired product were combined and dried under vacuum to afford Example 31 (8.9 mg, 12.54% yield). MS (ES): m/z=358.1 [M+H]⁺; HPLC Ret. Time 1.37 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.46 (s, 1H), 7.97 (s, 1H), 7.73-7.61 (m, 2H), 7.55 (d, J=9.5 Hz, 1H), 7.43 (d, J=7.1 Hz, 1H), 7.25-7.17 (m, 1H), 7.11-6.94 (m, 1H), 6.41-6.06 (m, 1H), 4.52 (td, J=16.0, 3.2 Hz, 2H), 2.13 (s, 3H).

The examples shown in Table 7 have been prepared analogous to Example 31, using Intermediate 15D and various boronates.

TABLE 7 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 32

4-(6-(1-(2,2-difluoroethyl)-4-(6- methylpyridin-2-yl)-1H- imidazol-5-yl)imidazo[1,2- a]pyridin-3-yl)morpholine 425.2 1.404 H 33

ethyl 6-(1-(2,2-difluoroethyl)-4- (6-methylpyridin-2-yl)-1H- imidazol-5-yl)imidazo[1,2- a]pyridine-3-carboxylate 412.2 1.527 0.983 H I 34

N-(tert-butyl)-6-(1-(2,2- difluoroethyl)-4-(6- methylpyridin-2-yl)-1H- imidazol-5-yl)imidazo[1,2- a]pyridin-3-amine 411.2 1.679 1.023 H I

Example 35: methyl (6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-yl)carbamate

To a solution of Example 29 (30 mg, 0.085 mmol) in DCM (2 mL) was added TEA (0.035 mL, 0.254 mmol) and methyl chloroformate (7.21 μL, 0.093 mmol) at 0° C. The reaction mixture was stirred at RT for 3 h. The reaction mixture was diluted with DCM. The organic layer was washed with water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method M). Fractions containing the desired product were combined and dried under vacuum to afford Example 35 (3.6 mg, 10.31% yield). MS (ES): m/z=413.1 [M+H]⁺; HPLC Ret. Time 1.241. (HPLC Method C); ¹H NMR (400 MHz, DMSO-d₆) d ppm 9.58 (brs, 1H), 8.30 (d, J=1.0 Hz, 1H), 7.96 (s, 1H), 7.72-7.53 (m, 3H), 7.47 (s, 1H), 7.27-7.18 (m, 1H), 7.05-6.95 (m, 1H), 6.45-6.07 (m, 1H), 4.54-4.37 (m, 2H), 3.67 (br. s., 3H), 2.12 (s, 3H).

The example shown in Table 8 has been prepared analogous to Example 35, using example 29 and acetyl chloride.

TABLE 8 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 36

N-(6-(1-(2,2- difluoroethyl)-4-(6- methylpyridin-2-yl)- 1H-imidazol-5- yl)imidazo[1,2- a]pyridin-3- yl)acetamide 397.2 1.104 0.513 H I

Example 37: 2-(6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-yl)propan-2-ol

To a solution of Example 33 (30 mg, 0.073 mmol) in THF (2 mL) was added methylmagnesium chloride (0.122 mL, 0.365 mmol) at 0° C. The reaction mixture was stirred at RT for 2 h and quenched with saturated aq. NH₄Cl solution. The aq. phase was extracted with EtOAc. The organic layer was washed with water, brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method O). Fractions containing the desired product were combined and dried under vacuum to afford Example 37 (3 mg, 10.35% yield). MS (ES): m/z=398.1 [M+H]⁺; HPLC Ret. Time 1.231 and 0.600 min. (HPLC Methods H and I, respectively); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.69 (s, 1H), 7.94 (s, 1H), 7.69-7.55 (m, 3H), 7.43 (s, 1H), 7.25-7.18 (m, 1H), 6.98 (d, J=7.6 Hz, 1H), 6.44-6.09 (m, 1H), 5.32 (br. s., 1H), 4.50-4.36 (m, 2H), 1.90 (s, 3H), 1.57 (s 6H).

Example 38: (6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-yl)methanol

To a solution of Example 33 (160 mg, 0.389 mmol) in DCM (5 mL) was added DIBAL-H (1.556 mL, 1.556 mmol) at −78° C. The reaction mixture was slowly warmed to RT, stirred for 2 h and quenched with aqueous saturated sodium potassium tartarate solution. The aqueous phase was extracted with EtOAc. The organic layer was washed with water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method M). Fractions containing the desired product were combined and dried under vacuum to afford Example 38 (120 mg, 84% yield). MS (ES): m/z=370.1 [M+H]⁺; HPLC Ret. Time 1.06 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.52 (s, 1H), 7.96 (s, 1H), 7.71-7.56 (m, 4H), 7.30 (dd, J=9.0, 1.5 Hz, 1H), 6.99 (d, J=7.6 Hz, 1H), 6.40-6.03 (m, 1H), 5.25 (t, J=5.3 Hz, 1H), 4.81 (d, J=5.1 Hz, 2H), 4.48 (td, J=16.0, 2.8 Hz, 2H), 2.11 (s, 3H).

Example 39: N-(6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridin-3-yl)-2,2,2-trifluoroacetamide

A solution of Example 34 (30 mg, 0.073 mmol) in TFA (0.3 mL) was heated at 70° C. for 1 h. The reaction mixture was quenched with 10% aqeuous solution of NaHCO₃. The aqueous phase was extracted with DCM. The organic layer was washed with water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method M). Fractions containing the desired product were combined and dried under vacuum to afford Example 39 (2.1 mg, 6.12% yield). MS (ES): m/z=451.1 [M+H]⁺; HPLC Ret. Time 1.25 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.71 (br. s., 1H), 7.98 (s, 1H), 7.86 (br. s., 1H), 7.77-7.49 (m, 4H), 7.00 (d, J=7.6 Hz, 1H), 6.42-6.06 (m, 1H), 4.54-4.41 (m, 2H), 2.10 (s, 3H).

Intermediate 40A: N-(4-(6-methylpyridin-2-yl)-1H-imidazol-2-yl)acetamide

To a solution of Intermediate 15A (5.0 g, 23.36 mmol) in DMF (100 mL) was added N-carbamimidoylacetamide (7.08 g, 70.1 mmol). The reaction mixture was stirred at RT for 64 h. The reaction mixture was diluted with EtOAc. The organic layer was washed with water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated to give the crude residue, which was triturated with Et₂O to afford Intermediate 40A (1.8 g, 35.6% yield). MS (ES): m/z=217.2 [M+H]⁺; HPLC Ret. Time 0.68 min. (HPLC Method G).

Intermediate 40B: N-(5-bromo-4-(6-methylpyridin-2-yl)-1H-imidazol-2-yl)acetamide

Intermediate 40B was synthesized analogous to Intermediate 15B (Scheme 3) by treating intermediate 40A with NBS. The crude product was triturated with hexanes and filtered to afford intermediate 40B (240 mg, 35.2% yield). MS (ES): m/z=295.2 [M+H]⁺; HPLC Ret. Time 1.750 min. (HPLC Method J.

Example 40: N-(5-(3-cyanoimidazo[1,2-a]pyridin-6-yl)-4-(6-methylpyridin-2-yl)-1H-imidazol-2-yl)acetamide

To a solution of Intermediate 40B (100 mg, 0.340 mmol) in 1,4-dioxane (5 mL)/water (0.5 mL) was added 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile (137 mg, 0.510 mmol) and potassium phosphate, tribasic (148 mg, 0.850 mmol). The solution was purged with nitrogen for 2 min. and PdCl₂(dppf)-CH₂Cl₂ adduct (27.8 mg, 0.034 mmol) was added. The reaction mixture was heated at 100° C. for 16 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method N). Fractions containing the desired product were combined and dried under vacuum to afford Example 40 (2.6 mg, 2.1% yield). MS (ES): m/z=358.1 [M+H]⁺; HPLC Ret. Time 1.423 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 11.71-12.17 (m, 1H), 11.30-11.49 (m, 1H), 9.06-9.18 (m, 1H), 8.44-8.50 (m, 1H), 7.78-7.95 (m, 2H), 7.65-7.74 (m, 1H), 7.08-7.42 (m, 2H), 2.55 (s, 3H), 2.11 (s, 3H).

Example 41: N-(5-(imidazo[1,2-a]pyridin-6-yl)-4-(6-methylpyridin-2-yl)-1H-imidazol-2-yl)acetamide

Example 41 was synthesized analogous to Example 440 (Scheme 15) by treating Intermediate 40B with 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine. The crude product was purified via preparative HPLC (Method Q). Fractions containing the product were combined and evaporated to afford Example 41 (6.2 mg, 5.6% yield). MS (ES): m/z=333.2 [M+H]⁺; HPLC Ret. Time 1.233 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 11.20-11.93 (m, 1H), 8.81-9.05 (m, 1H), 7.96-8.03 (m, 1H), 7.56-7.62 (m, 4H), 7.39 (dd, J=9.41, 1.59 Hz, 1H), 7.26 (d, J=8.31 Hz, 1H), 7.10 (d, J=7.58 Hz, 1H), 2.33 (s, 3H), 2.14 (s, 3H).

Intermediate 42A: 2-((3,3-difluorocyclobutyl)amino)-1-(6-methylpyridin-2-yl)ethanone HCl

To a solution of 3,3-difluorocyclobutanamine (0.600 g, 5.61 mmol) in acetonitrile (10 mL) was added K₂CO₃ (1.614 g, 11.68 mmol) and Intermediate 15A (1.0 g, 4.67 mmol) at 0° C. The reaction mixture was stirred at RT for 18 h and then filtered through a Celite® pad. Concentrated HCl was added to the filtrate and evaporated in vacuo to afford Intermediate 42A (0.8 g, 71% yield) as the HCl salt. MS (ES): m/z=241.2 [M+H]⁺; HPLC Ret. Time 1.897 min. (HPLC Method J).

Intermediate 42B: 2-(1-(3,3-difluorocyclobutyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 42B was synthesized analogous to intermediate 15B (Scheme 3) by treating Intermediate 46A with formamide. The crude residue was purified by silica gel chromatography (120 g RediSep® column, eluting with a gradient from 60-70% EtOAc in petroleum ether). Fractions containing the product were combined and evaporated to afford Intermediate 42B (210 mg, 40.5% yield). MS (ES): m/z=250.1 [M+H]; HPLC Ret. Time 2.14 min. (HPLC Method J).

Intermediate 42C: 2-(5-bromo-1-(3,3-difluorocyclobutyl)-1H-imidazol-4-yl)-6-methylpyridine

Intermediate 42C was synthesized analogous to Intermediate 15B by treating Intermediate 42B with NBS. The crude residue was triturated with hexanes to afford Intermediate 46C (78 mg, 11.8% yield). MS (ES): m/z=328.0 [M+2H]⁺; HPLC Ret. Time 2.136 min. (HPLC Method J).

Example 42: 6-(1-(3,3-difluorocyclobutyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-a]pyridine-3-carbonitrile

To a solution of Intermediate 42C (0.061 g, 0.186 mmol) 1,4-dioxane (5 mL) was added 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile (0.05 g, 0.186 mmol) and aqueous Na₂CO₃ (0.233 mL, 0.466 mmol). The solution was purged with argon for 2 min. and PdCl₂(dppf)-CH₂Cl₂ adduct (0.015 g, 0.019 mmol) was added. The reaction mixture was heated at 90° C. for 18 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 42 (1.1 mg, 1.5% yield). MS (ES): m/z=391.0 [M+H]⁺; HPLC Ret. Time 1.58 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.88 (s, 1H), 8.53 (s, 1H), 8.23 (s, 1H), 7.88 (d, J=9.0 Hz, 1H), 7.73 (d, J=8.1 Hz, 1H), 7.67-7.59 (m, 2H), 7.01 (d, J=8.1 Hz, 1H), 4.66 (br. s., 1H), 3.26-3.13 (m, 2H), 3.08-2.97 (m, 2H), 2.11 (s, 3H).

Example 43: 6-(1-(2,2-difluoroethyl)-4-(6-methoxypyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 43 was synthesized analogous to Example 5 by treating Intermediate 43A (reference: WO 2016/140884 A1) with 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-3-carbonitrile. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 43 (2.1 mg, 3.8% yield). MS (ES): m/z=382.1 [M+H]⁺; HPLC Ret. Time 1.56 min. (HPLC Method H). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.64 (s, 1H), 8.40 (d, J=9.54 Hz, 1H), 8.06 (s, 1H), 7.73-7.79 (m, 1H), 7.63-7.72 (m, 2H), 6.67 (dd, J=0.98, 8.07 Hz, 1H) 6.19-6.52 (m, 1H), 4.68 (dt, J=3.30, 15.34 Hz, 2H), 3.16 (s, 3H).

Intermediate 44B: 6-(1-methyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

To a solution of Intermediate 44A (200 mg, 0.947 mmol) in 1,2 dichlorobenzene (3 mL) was added methanamine (0.24 mL, 1.894 mmol) and TFA (216 mg, 1.894 mmol). The reaction mixture was heated in a microwave instrument at 200° C. for 2 h, then cooled to RT and diluted with a solution of 10% MeOH in DCM. The organic layer was washed with 10% aqueous solution of NaOH, water and brine, dried over anhydrous Na₂SO₄, filtered and the filtrate concentrated in vacuo. The crude residue was purified by silica gel chromatography (40 g RediSep® column, eluting with a gradient from 0-20% MeOH in DCM). Fractions containing the product were combined and evaporated to afford Intermediate 44B (150 mg, 68.5% yield). MS (ES): m/z=225.4 [M+H]⁺; HPLC Ret. Time 0.74 min. (HPLC Method G).

Intermediate 44C: 6-(4-bromo-1-methyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 44C was synthesized analogous to Intermediate 15D by treating Intermediate 44B with NBS. The crude residue was triturated with petroleum ether to afford Intermediate 50C (0.15 g, 82% yield). MS (ES): m/z=305.0 [M+2H]⁺; HPLC Ret. Time 1.353 min. (HPLC Method J).

Example 44: 6-(1-methyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

To a solution of Intermediate 44C (100 mg, 0.330 mmol) in 1,4-dioxane (5 mL) was added 2-methyl-6-(tributylstannyl)pyridine (0.334 mL, 0.990 mmol). The solution was purged with argon for 2 min. and Pd(PPh₃)₄ (38.1 mg, 0.033 mmol) was added. The reaction mixture was heated at 100° C. for 18 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 44 (4.7 mg, 4.6% yield). MS (ES): m/z=316.1 [M+H]⁺; HPLC Ret. Time 1.31 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.61 (s, 1H), 8.32 (d, J=9.54 Hz, 1H), 7.99 (s, 1H), 7.76-7.80 (m, 1H), 7.67-7.75 (m, 2H), 7.09 (d, J=6.85 Hz, 1H), 3.76 (s, 3H), 2.16 (s, 3H).

Example 45: 6-(1-methyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

To a solution of Example 44 (50 mg, 0.159 mmol) in DMSO (3 mL) was added K₂CO₃ (43.8 mg, 0.317 mmol) and H₂O₂ (0.097 mL, 1.586 mmol, 30% aq. solution) at 0° C. The reaction mixture was stirred at RT for 2 h and then diluted with EtOAc and water. The layers were separated and the aqueous layer was extracted with EtOAc. The combined organic layer was washed with brine, dried over anhydrous Na₂SO₄, filtered and the filtrate was concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method N). Fractions containing the desired product were combined and dried under vacuum to afford Example 45 (9.1 mg, 17.04% yield). MS (ES): m/z=334.1 [M+H]⁺; HPLC Ret. Time 0.96 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.32 (s, 1H), 8.26 (d, J=9.54 Hz, 1H), 7.97 (s, 1H), 7.90 (br. s., 1H), 7.78 (d, J=7.58 Hz, 2H), 7.67-7.74 (m, 1H), 7.59 (d, J=9.54 Hz, 1H), 7.08 (d, J=7.58 Hz, 1H), 3.75 (s, 3H), 2.14 (s, 3H).

Intermediate 46A: 6-(1-(2-hydroxy-2-methylpropyl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 46A was synthesized analogous to Intermediate 44B by treating Intermediate 44A with 1-amino-2-methylpropan-2-ol. The crude residue was purified by silica gel chromatography (24 g RediSep® column, eluting with a gradient from 0-20% MeOH in DCM). Fractions containing the product were combined and evaporated to afford Intermediate 46A (0.12 g, 15.3% yield). MS (ES): m/z=283.4 [M+H]⁺; HPLC Ret. Time 0.52 min. (HPLC Method F).

Intermediate 46B: 6-(4-bromo-1-(2-hydroxy-2-methylpropyl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 46B was synthesized analogous to Intermediate 15D by treating Intermediate 46A with NBS. The crude residue was triturated with petroleum ether to afford Intermediate 52B (80 mg). MS (ES): m/z=361.4 [M+H]⁺; HPLC Ret. Time 0.85 min. (HPLC Method F).

Example 46: 6-(1-methyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 46 was synthesized analogous to Example 44 by treating Intermediate 46B with 2-methyl-6-(tributylstannyl)pyridine. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 46 (2 mg, 2.4% yield). MS (ES): m/z=374.2 [M+H]⁺; HPLC Ret. Time 1.33 min. (HPLC Method H). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.63 (s, 1H), 8.30 (d, J=9.29 Hz, 1H), 8.12 (s, 1H), 7.71-7.80 (m, 2H), 7.64 (d, J=9.54 Hz, 1H), 6.95-7.24 (m, 1H), 4.17 (s, 2H), 2.20 (s, 3H), 0.98 (s, 6H).

Example 47: 6-(1-(2,2-difluoroethyl)-4-(pyridin-3-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

To a solution of Intermediate 43A (30 mg, 0.085 mmol) in 1,4-dioxane (1 mL)/ethanol (0.5 mL)/water (0.5 mL) was added pyridin-3-ylboronic acid (15.66 mg, 0.127 mmol) and K₃PO₄ (54.1 mg, 0.255 mmol). The solution was purged with argon for 2 min. and Pd(PPh₃)₂Cl₂ (6.22 mg, 8.50 tmol) was added. The reaction mixture was heated in a microwave instrument at 100° C. for 1 h, cooled to RT and concentrated in vacuo. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 47 (3.2 mg, 10.72% yield). MS (ES): m/z=352.2 [M+H]⁺; HPLC Ret. Time 0.99 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) d ppm 8.71 (dd, J=0.86, 2.3 Hz, 1H), 8.65 (s, 1H), 8.52 (dd, J=1.6, 4.77 Hz, 1H), 8.34 (d, J=9.54 Hz, 1H), 8.15 (s, 1H), 7.85-7.94 (m, 1H), 7.38 (ddd, J=0.98, 4.77, 7.95 Hz, 1H), 7.33 (d, J=9.54 Hz, 1H), 6.26-6.61 (m, 1H), 4.81 (dt, J=3.42, 15.16 Hz, 2H).

The examples shown in Table 9 have been prepared analogous to Example 47, using Intermediate 43A and various boronic acids.

TABLE 9 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 48

6-(1-(2,2-difluoroethyl)-4- (pyridin-4-yl)-1H-imidazol-5- yl)imidazo[1,2-b]pyridazine-3- carbonitrile 352.2 1.034 0.773 H I 49

6-(4-(2-chloropyridin-4-yl)-1- (2,2-difluoroethyl)-1H- imidazol-5-yl)imidazo[1,2- b]pyridazine-3-carbonitrile 386.2 1.261 1.239 H I 50

6-(1-(2,2-difluoroethyl)-4- (pyrimidin-5-yl)-1H-imidazol- 5-yl)imidazo[1,2-b]pyridazine- 3-carbonitrile 353.2 0.923 0.888 H I 51

6-(4-(5-aminopyridin-3-yl)-1- (2,2-difluoroethyl)-1H- imidazol-5-yl)imidazo[1,2- b]pyridazine-3-carbonitrile 367.2 0.907 0.770 H I 52

6-(4-(2-cyanopyridin-4-yl)-1- (2,2-difluoroethyl)-1H- imidazol-5-yl)imidazo[1,2- b]pyridazine-3-carbonitrile 377.2 1.187 1.176 H I 53

6-(1-(2,2-difluoroethyl)-4- (thiophen-3-yl)-1H-imidazol- 5-yl)imidazo[1,2-b]pyridazine- 3-carbonitrile 357.1 1.323 1.067 H I 54

6-(1-(2,2-difluoroethyl)-4- (thiophen-2-yl)-1H-imidazol- 5-yl)imidazo[1,2-b]pyridazine- 3-carbonitrile 357.2 1.326 1.231 H I 55

6-(4-(benzo[b]thiophen-2-yl)- 1-(2,2-difluoroethyl)-1H- imidazol-5-yl)imidazo[1,2- b]pyridazine-3-carbonitrile 407.2 1.676 1.643 H I

Example 56: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 56 was synthesized by reacting Intermediate 43A with 2-methyl-6-(tributylstannyl)pyridine and by employing the experimental procedure described for Example 44 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 56 (6.8 mg, 13.56% yield). MS (ES): m/z=366.1 [M+H]⁺; HPLC Ret. Time 1.60 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.61 (s, 1H), 8.31 (d, J=10.0 Hz, 1H), 8.06 (s, 1H), 7.80 (d, J=7.6 Hz, 1H), 7.68-7.75 (m, 2H), 7.11 (d, J=7.2 Hz, 1H), 6.40 (tt, J 3.2, 55.5 Hz, 1H), 6.75 (dt, J=3.2, 15.2 Hz, 2H), 2.16 (s, 3H).

Example 57: 6-(1-(2,2-difluoroethyl)-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

Example 57 was synthesized by reacting Example 56 with H₂O₂/K₂CO₃ and by employing the experimental procedure described for Example 45 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 57 (5.6 mg, 10.6% yield). MS (ES): m/z=384.1 [M+H]⁺; HPLC Ret. Time 1.18 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.33 (s, 1H), 8.21 (d, J=9.2 Hz, 1H), 8.04 (s, 1H), 7.90 (bs, 1H), 7.70-7.80 (m, 3H), 7.51 (d, J=9.6 Hz, 1H), 7.10 (d, J=7.6 Hz, 1H), 6.54 (t, J=54.8 Hz, 1H), 4.69 (t, J=14.0 Hz, 2H), 2.14 (s, 3H).

Intermediate 58A: 6-(1-neopentyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 58A was synthesized by reacting Intermediate 44A with 2,2-dimethylpropan-1-amine and by employing the experimental procedure described for intermediate 44B in Scheme 19. The crude product was purified by silica gel chromatography (24 g RediSep® column, eluting with a gradient of 5-10% MeOH in chloroform). Fractions containing the desired product were combined and evaporated to afford Intermediate 58A (160 mg, 60.3% yield). MS (ES): m/z=281.2 [M+H]⁺; HPLC Ret. Time 2.11 min. (HPLC Method J).

Intermediate 58B: 6-(4-bromo-1-neopentyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 58B was synthesized by reacting Intermediate 58A with NBS and by employing the experimental procedure described for Intermediate 15D in Scheme 3 to afford Intermediate 58B. MS (ES): m/z=359.8 [M+H]⁺; HPLC Ret. Time 2.39 min. (HPLC Method K).

Example 58: 6-(4-(6-methylpyridin-2-yl)-1-neopentyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 58 was synthesized by reacting Intermediate 58B with 2-methyl-6-(tributylstannyl)pyridine and by employing the experimental procedure described for Example 46 in Scheme 20. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 44 (5.6 mg, 10.72% yield). MS (ES): m/z=372.2 [M+H]⁺; HPLC Ret. Time 1.87 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.65 (s, 1H), 8.34 (d, J=9.6 Hz, 1H), 8.12 (s, 1H), 7.72-7.77 (m, 3H), 7.15-7.17 (m, 1H), 4.12 (s, 2H), 2.194 (s, 3H), 0.75 (s, 9H).

Example 59: 6-(4-(6-methylpyridin-2-yl)-1-neopentyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

Example 59 was synthesized by reacting Example 58 with H₂O₂/K₂CO₃ and by employing the experimental procedure described for Example 45 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 59 (6.4 mg, 10.07% yield). MS (ES): m/z=390.2 [M+H]⁺; HPLC Ret. Time 1.42 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.31 (s, 1H), 8.24 (d, J=9.6 Hz, 1H), 7.97 (s, 1H), 7.78-7.86 (m, 3H), 7.70 (t, J=7.6 Hz, 1H), 7.59 (d, J=9.2 Hz, 1H), 7.05 (d, J=7.2 Hz, 1H), 4.12 (s, 2H), 2.10 (s, 3H), 0.69 (s, 9H).

Intermediate 60A: 6-(1-isopropyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 60A was synthesized by reacting Intermediate 44A with propan-2-amine and by employing the experimental procedure described for Intermediate 44B in Scheme 19. The crude product was purified by silica gel chromatography (24 g RediSep® column, eluting with a gradient of 5-10% MeOH in chloroform). Fractions containing the desired product were combined and evaporated to afford Intermediate 60A (85.5 mg, 47.7% yield). MS (ES): m/z=253.0 [M+H]⁺; HPLC Ret. Time 0.95 min. (HPLC Method G).

Intermediate 60B: 6-(4-bromo-1-isopropyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 60B was synthesized by reacting Intermediate 60A with NBS and by employing the experimental procedure described for Intermediate 16B in Scheme 3 to afford Intermediate 60B (225 mg, 95% yield). MS (ES): m/z=331.0 [M+H]⁺; HPLC Ret. Time 1.07 min. (HPLC Method G).

Example 60: 6-(1-isopropyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 60 was synthesized by reacting Intermediate 60B with 2-methyl-6-(tributylstannyl)pyridine and by employing the experimental procedure described for Example 44 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 60 (120 mg, 52.6% yield). MS (ES): m/z=344.0 [M+H]⁺; HPLC Ret. Time 1.56 min. (HPLC Method G); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.61 (s, 1H), 8.32 (d, J=9.6 Hz, 1H), 8.22 (s, 1H), 7.77 (d, J=8.0 Hz, 1H), 7.67-7.71 (m, 2H), 7.05 (d, J=10.0 Hz, 1H), 4.48-4.55 (m, 1H), 2.09 (s, 3H), 1.49 (d, J=6.8 Hz, 6H).

Example 61: 6-(1-isopropyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

Example 61 was synthesized by reacting Example 60 with H₂O₂/K₂CO₃ and by employing the experimental procedure described for Example 45 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 61 (8.8 mg, 13.94% yield). MS (ES): m/z=362.1 [M+H]⁺; HPLC Ret. Time 1.15 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.33 (s, 1H), 8.28 (d, J=9.6 Hz, 1H), 8.21 (s, 1H), 7.86 (bs, 2H), 7.77 (d, J=8.0 Hz, 1H), 7.67 (t, J=7.6 Hz, 1H), 7.55 (d, 9.2 Hz, 1H), 7.03 (d, J=7.2 Hz, 1H), 4.52-4.56 (m, 1H), 2.06 (s, 3H), 1.45 (d, J=6.8 Hz, 6H).

Intermediate 62A: 6-(1-ethyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 62A was synthesized by reacting Intermediate 44A with ethyl amine and by employing the experimental procedure described for Intermediate 44B in Scheme 19. The crude product was purified by silica gel chromatography (24 g RediSep® column, eluting with a gradient of 5-10% MeOH in chloroform). Fractions containing the desired product were combined and evaporated to afford Intermediate 62A (118 mg, 52.3% yield). MS (ES): m/z=239.1 [M+H]⁺; HPLC Ret. Time 0.42 min. (HPLC Method G).

Intermediate 62B: 6-(4-bromo-1-ethyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 62B was synthesized by reacting Intermediate 62A with NBS and by employing the experimental procedure described for Intermediate 16B in Scheme 3 to afford Intermediate 62B (109 mg, 71.2% yield). MS (ES): m/z=317.2 [M+H]⁺; HPLC Ret. Time 0.27 min. (HPLC Method G).

Example 62: 6-(1-ethyl-4-(6-methylpyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 62 was synthesized by reacting Intermediate 62B with 2-methyl-6-(tributylstannyl)pyridine and by employing the experimental procedure described for Example 44 in Scheme 19. The crude product was dissolved in DMF and purified via preparative HPLC (Condition P). Fractions containing the desired product were combined and dried under vacuum to afford Example 62 (2.4 mg, 2.1% yield). MS (ES): m/z=330.1 [M+H]⁺; HPLC Ret. Time 1.50 min. (HPLC Method H); ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.61 (s, 1H), 8.32 (d, J=9.6 Hz, 1H), 8.07 (s, 1H), 7.78 (d, J=7.6 Hz, 1H), 7.68-7.73 (m, 2H), 7.07 (d, J=8.0 Hz, 1H), 4.13 (q, J=7.2 Hz, 2H), 2.13 (s, 3H), 1.35 (t, J=7.2 Hz, 3H).

Example 63: 6-(1-(2,2-difluoroethyl)-4-(6-methoxypyridin-3-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 63 was synthesized by reacting Intermediate 43A with (6-methoxypyridin-3-yl)boronic acid and by employing the experimental procedure described for Example 43 in Scheme 18. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 63 (14.5 mg, 25.5% yield). MS (ES): m/z=382.1 [M+H]⁺; HPLC Ret. Time 1.426 and 1.060 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.63 (s, 1H), 8.25-8.34 (m, 2H), 8.10 (s, 1H), 7.84 (dd, J 2.57, 8.68 Hz, 1H), 7.31 (d, J 9.29 Hz, 1H), 6.82 (dd, J 0.73, 8.56 Hz, 1H), 6.27-6.60 (m, 1H), 4.80 (dt, J 3.42, 15.16 Hz, 2H), 3.85 (s, 3H).

Example 64: 6-(1-(2,2-difluoroethyl)-4-(6-methoxypyridin-3-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

Example 64 was synthesized by reacting Example 63 with H₂O₂/K₂CO₃ and by employing the experimental procedure described for Example 45 in Scheme 19. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 64 (12.9 mg, 15.24% yield). MS (ES): m/z=400.1 [M+H]⁺; HPLC Ret. Time 1.131 and 0.927 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.35 (s, 1H), 8.22-8.27 (m, 2H), 8.06 (s, 1H), 7.90 (br. s., 1H), 7.79 (dd, J=2.45, 8.80 Hz, 2H), 7.19 (d, J=9.54 Hz, 1H), 6.80 (d, J=8.56 Hz, 1H), 6.39-6.71 (m, 1H), 4.74 (dt, J=3.18, 15.41 Hz, 2H), 3.84 (s, 3H).

Example 65: 6-(1-(2,2-difluoroethyl)-4-(6-fluoropyridin-3-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 65 was synthesized by reacting Intermediate 43A with (6-(6-fluoropyridin-3-yl)boronic acid and by employing the experimental procedure described for Example 43 in Scheme 18. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 65 (4.5 mg, 8.52% yield). MS (ES): m/z=370.1 [M+H]⁺; HPLC Ret. Time 1.354 and 1.295 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.66 (s, 1H), 8.31-8.39 (m, 2H), 8.06-8.17 (m, 2H), 7.37 (d, J=9.54 Hz, 1H), 7.18 (dd, J=2.69, 8.56 Hz, 1H), 6.28-6.61 (m, 1H), 4.82 (dt, J=3.18, 15.16 Hz, 2H).

Example 66: 6-(1-(2,2-difluoroethyl)-4-(6-fluoropyridin-3-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carboxamide

Example 66 was synthesized by reacting Example 65 with H₂O₂/K₂CO₃ and by employing the experimental procedure described for Example 45 in Scheme 19. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 66 (16 mg, 15.10% yield). MS (ES): m/z=388.1 [M+H]⁺; HPLC Ret. Time 0.985 and 0.919 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.37 (s, 1H), 8.34 (d, J=2.20 Hz, 1H), 8.27 (d, J=9.54 Hz, 1H), 8.12 (s, 1H), 8.05 (dt, J=2.57, 8.25 Hz, 1H), 7.89 (br. s., 1H), 7.76 (br. s., 1H), 7.24 (d, J=9.29 Hz, 1H), 7.16 (dd, J=2.81, 8.44 Hz, 1H), 6.40-6.72 (m, 1H), 4.70-4.82 (m, 2H).

Example 67: 6-(1-isopropyl-4-(6-(trifluoromethyl)pyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

To a solution of 2-bromo-6-(trifluoromethyl)pyridine (100 mg, 0.4424 mmol) in 1,4-dioxane (5 mL) was added 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (123.5 mg, 0.4867 mmol) and potassium acetate (173.6 mg, 1.769 mmol). The solution was purged with argon for 2 min. and PdCl₂(dppf) (64.7 mg, 0.088 mmol) was added. The reaction mixture was heated at 100° C. for 16 h. The reaction mixture was then cooled to RT and partitioned between water and ethyl acetate. The organic layer was washed with brine, dried over anhydrous Na₂SO₄ to afford Intermediate 67A (62 mg crude).

Example 67 was synthesized by reacting Intermediate 67A with Intermediate 60B and by employing the experimental procedure described for Example 43 in Scheme 18. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method R). Fractions containing the desired product were combined and dried under vacuum to afford Example 67 (7.4 mg, 12.21% yield). MS (ES): m/z=398.1 [M+H]⁺; HPLC Ret. Time 1.868 and 1.621 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.65 (s, 1H), 8.38 (d, J=9.54 Hz, 1H), 8.31 (s, 1H), 8.25 (d, J=8.3 Hz, 1H), 8.10 (t, J=7.95 Hz, 1H), 7.71 (d, J=9.3 Hz, 1H), 7.66 (d, J=7.6 Hz, 1H), 4.43-4.53 (m, 1H), 1.51 (d, J=6.6 Hz, 6H).

The example shown in Table 10 has been prepared analogous to Example 67, using Intermediate 60B and the boronate ester generated from 2-bromo-6-(difluoromethoxy)pyridine.

TABLE 10 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 68

6-(4-(6- (difluoromethoxy)pyridin- 2-yl)-1-isopropyl-1H- imidazol-5- yl)imidazo[1,2- b]pyridazine-3- carbonitrile 396.2 1.91 K

Intermediate 69A: 6-(1-cyclopropyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 69A was synthesized by reacting Intermediate 44A with cyclopropanamine and by employing the experimental procedure described for intermediate 44B in Scheme 19. The crude product was purified by silica gel chromatography (40 g RediSep® column, eluting with a gradient of 0-20% MeOH in DCM). Fractions containing the desired product were combined and evaporated to afford Intermediate 69A (280 mg, 41.6% yield). LCMS: m/z=251.1 [M+H]⁺; HPLC Ret. Time 0.66 min. (HPLC Method F).

Intermediate 69B: 6-(4-bromo-1-cyclopropyl-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Intermediate 69B was synthesized by reacting Intermediate 69A with NBS and by employing the experimental procedure described for Intermediate 16B in Scheme 3 to afford Intermediate 69B (360 mg, 70.4% yield). LCMS: m/z=331.0 [M+H]⁺; HPLC Ret. Time 1.20 min. (HPLC Method F).

Example 69: 6-(1-cyclopropyl-4-(6-(trifluoromethyl)pyridin-2-yl)-1H-imidazol-5-yl)imidazo[1,2-b]pyridazine-3-carbonitrile

Example 69 was synthesized by reacting Intermediate 69B with Intermediate 67A and by employing the experimental procedure described for Example 43 in Scheme 18. The crude product was dissolved in a mixture of DMF and methanol and purified via preparative HPLC (Method P). Fractions containing the desired product were combined and dried under vacuum to afford Example 69 (1.3 mg, 2.1% yield). MS (ES): m/z=396.1 [M+H]⁺; HPLC Ret. Time 1.791 and 1.557 min. (HPLC Methods H and I, respectively). ¹H NMR (400 MHz, DMSO-d₆) δ ppm 8.66 (s, 1H), 8.44 (d, J=9.3 Hz, 1H), 8.23 (d, J=8.1 Hz, 1H), 8.06-8.15 (m, 2H), 7.81 (d, J=9.5 Hz, 1H), 7.68 (d, J=7.8 Hz, 1H), 3.52 (brs, 1H), 1.01 (brs, 2H), 0.91 (d, J=6.6 Hz, 2H).

The example shown in Table 11 has been prepared analogous to Example 69, using Intermediate 69B and the boronate ester generated from 2-bromo-6-(difluoromethoxy)pyridine.

TABLE 11 Ret Time HPLC Ex. Structure Name [M + H]⁺ (min.) Method 70

6-(1-cyclopropyl-4-(6- (difluoromethoxy)pyridin- 2-yl)-1H-imidazol-5- yl)imidazo[1,2- b]pyridazine-3- carbonitrile 394.1 1.729 1.460 H I

Biological Assays

Assays are conducted in 1536-well plates and 2 μL reactions are prepared from addition of HIS-TGFβR1 T204D or HIS-TGFβR2 WT, anti-HIS detection antibody, a labeled small molecule probe (K_(d)=<100 nM; k_(off)=<0.001 s⁻¹) and test compounds in assay buffer (20 mM HEPES pH 7.4, 10 mM MgCl₂, 0.015% Brij35, 4 mM DTT, and 0.05 mg/ml BSA). The reaction is incubated for 1 hour at room temperature and the HTRF signal was measured on an Envision plate reader (Ex:340 nm; Em:520 nm/495 nm).

Inhibition data were calculated by comparison to no enzyme control reactions for 100% inhibition and vehicle-only reactions for 0% inhibition. The final concentration of reagents in the assay are 1 nM HIS-TGFβR1 T204D or HIS-TGFβR2 WT, 0.2 nM anti-HIS detection antibody, labeled small molecule prode (at K_(d)) and 0.5% DMSO. Dose response curves were generated to determine the concentration required inhibiting 50% of kinase activity (IC₅₀). Compounds were dissolved at 10 mM in dimethylsulfoxide (DMSO) and evaluated at eleven concentrations. IC₅₀ values were derived by non-linear regression analysis.

The table shows the TGFβR1 and TGFβR2 IC₅₀ values for the Examples of this invention.

Example # TGFbR2 (mM) TGFbR1 (mM) 1 >15.0 0.0013 2 >15.0 6.2970 3 >15.0 0.0031 4 >15.0 0.0015 5 >15.0 — 6 >50.0 5.7480 7 >15.0 0.0023 8 >15.0 0.0097 9 >15.0 0.0290 10 1.13 0.0003 11 >15.0 0.1870 12 0.187 0.0006 13 0.420 0.0003 14 — — 15 ~10.7 0.0016 16 ~3.28 0.0009 17 2.31 0.0012 18 2.16 0.0058 19 0.0821 0.0007 20 0.183 0.0008 21 0.0765 ~0.0005 22 0.028 ~0.0007 23 >15.0 0.0010 24 ~2.51 ~0.0003 25 — — 26 0.901 ~0.0004 27 >15.0 ~0.0013 28 >15.0 0.6524 29 >15.0 0.0165 30 >15.0 0.0575 31 >15.0 0.0011 32 >15.0 0.0056 33 0.701 0.0010 34 >15.0 0.0088 35 >15.0 0.0051 36 ~6.23 0.0020 37 ~9.08 0.0039 38 >15.0 0.0045 39 >15.0 0.0068 40 0.784 0.0005 41 ~6.4 0.0033 42 ~13.5 0.0296 43 >15.0 0.0013 44 3.49 0.0012 45 0.752 0.0011 46 3.32 0.0031 47 >15.0 0.4940 48 >15.0 0.2200 49 >15.0 0.0110 50 >15.0 ~10.00 51 >15.0 1.3920 52 >15.0 0.0740 53 ~8.04 0.0116 54 ~8.7 0.0301 55 >15.0 0.0803 56 1.16 0.0010 57 0.247 0.0007 58 0.351 0.0010 59 4.08 0.0035 60 0.319 0.0007 61 0.131 0.0006 62 0.66 >15.0 63 >15.0 0.0591 64 >15.0 0.0335 65 >15.0 0.1203 66 >15.0 0.0201 67 >15.0 0.0142 68 ~11.2 0.0016 69 ~12.3 0.0010 70 ~12.3 0.0053 

1. A compound having the structure of formula (I)

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof, wherein A is a 5-8 membered heterocyclic ring or a 10-12 membered heterobicyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 2. The compound according to claim 1 of formula (I):

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof, wherein A is pyridyl substituted with 0-3 R⁴ groups; each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 3. The compound according to claim 2, wherein A is pyridyl substituted with 0-2 R⁴ groups; each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 4. The compound according to claim 3, wherein Z is

and n is 0, 1 or
 2. 5. (canceled)
 6. (canceled)
 7. (canceled)
 8. The compound according to claim 1 of the formula

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.
 9. (canceled)
 10. (canceled)
 11. (canceled)
 12. The compound according to claim 1 of the formula

or a pharmaceutically acceptable salt, prodrug, or N-oxide thereof, or a solvate or hydrate thereof.
 13. The compound according to claim 1 of the formula

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof, wherein each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 14. The compound according to claim 1 of the formula

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof, wherein each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 15. The compound according to claim 1 of the formula

or a pharmaceutically acceptable salt, prodrug or N-oxide thereof, or solvate or hydrate thereof, wherein each R⁴ is independently hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkoxy, C₃-C₆ cycloalkyl, —NH₂, —NO₂, or —CN; Z is a 10-12 membered heterobicyclic ring substituted with 0-2 R^(Z) groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(Z) is independently halogen, —CN, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkenyl, C₃-C₆ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkanol, —COO C₁-C₆ alkyl, —CONR^(z1)R^(z2), —NHC(O) C₁-C₆ haloalkyl, —NHC(O) C₁-C₆ alkyl, —NH C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(z1) and R^(z2) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; R¹ is hydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkanol, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₆ cycloalkyl substituted with 0-2 R⁴ groups, CONR^(1a)R^(1b), —NHC(O) C₁-C₆ alkyl, —COOH, —COO C₁-C₆ alkyl or a 5-8 membered heterocyclic ring substituted with 0-3 R⁴ groups containing 1-4 heteroatoms selected from —O—, —S— or —N—; each R^(1a) and R^(1b) is independently hydrogen, C₁-C₆ alkyl or C₃-C₆ cycloalkyl; and R² is hydrogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkyloxy, C₃-C₈ cycloalkyl or —NHC(O) C₁-C₆ alkyl.
 16. A pharmaceutical composition which comprises a compound according to claim 1 or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, diluents or excipients.
 17. A combination pharmaceutical product comprising a compound according to claim 1 or a pharmaceutically acceptable salt thereof together with one or more other therapeutically active agents.
 18. (canceled)
 19. A compound according to claim 1 or a pharmaceutically acceptable salt thereof for use in the treatment of diseases or conditions for which a TGFßR antagonist is indicated.
 20. A compound or a pharmaceutically acceptable salt thereof for use according to claim 19, wherein the disease or condition is cancer.
 21. The use according to claim 20 wherein the cancer is small cell lung cancer, non-small cell lung cancer, triple-negative breast cancer, ovarian cancer, colorectal cancer, prostate cancer, melanoma, pancreatic cancer, multiple myeloma, T-acute lymphoblastic leukemia or AML.
 22. (canceled)
 23. A method of treating diseases or conditions for which a TGFßR antagonist is indicated in a subject in need thereof which comprises administering a therapeutically effective amount of compound according to claim 1 or a pharmaceutically acceptable salt thereof.
 24. The method of claim 23 wherein the disease or condition is cancer.
 25. The method of claim 24 wherein the compound is administered in combination with a therapeutically effective amount of one or more chemotherapeutic agents.
 26. A method for treating cancer in a subject in need thereof, comprising administering an effective amount of a compound, according to claim 1, or a pharmaceutically acceptable salt thereof, in combination with the administration of a therapeutically effective amount of one or more immuno-oncology agents.
 27. A method for treating a subject afflicted with cancer comprising administering to the subject a therapeutically effective amount of: a) a compound according to claim 1, or a pharmaceutically acceptable salt thereof, and b) an anti-cancer agent which is an antibody or an antigen-binding portion thereof that binds specifically to a Programmed Death-1 (PD-1) receptor and inhibits PD-1 activity.
 28. The method of claim 27, wherein the anti-PD-1 antibody is nivolumab. 